Plural intrinsic expiration initiation application indicators

ABSTRACT

A device and method for monitoring the expiration of goods includes a substrate, a coating of polydiacetylene, said coating having properties of (1) changing from a first color irreversibly to a second color immediately upon being subjected to a specified temperature and (2), upon activation upon contact by an activating agent, changing from said first color to said second color at a temperature lower than said specified temperature after a time delay of at least one hour and an activating agent on a portion but not all of said coating.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of application Ser. No.10/226,379 filed Aug. 23, 2002, now U.S. Pat. No. 6,787,108 and is basedupon and claims the benefit of Provisional Patent Application Ser. No.60/369,309 filed Apr. 2, 2002.

BACKGROUND OF THE INVENTION

There is a general need to know whether perishable products andmaterials have or have not expired prior to consumption or use. Forexample, it is important to know in restaurants that uncooked meats andpoultry have been properly stored at low temperatures and have notexceeded the time frame necessary to maintain freshness. Proportionedfoods are periodically turned over and it is critical to monitor thetiming and turnover rate accurately to ensure patron safety. In foodservice organizations, large quantities of perishable foods must beinventoried in preparation for designated preparations. Often largepans, containers, and vats must be periodically used and cycled. It istherefore essential to monitor directly the time and temperature historyof perishable food items to ensure maximum freshness and minimumpotential pathogenic colonization.

There is concern by food and beverage producers that the products theyproduce are properly handled throughout the distribution cycle and thatsafe time and storage temperatures are maintained. It is desirable thatat the specific time a perishable item is produced that the time andtemperature profile of the food item be monitored cost effectively anddirectly without the need of employing complicated monitoring equipmentor devices which require special handling and storage.

Although dating and color labeling can be used as a means to distinguishand inventory a particular perishable item, complications arise inkeeping track of dates, knowing the correct date used, correlating afuture date with the present date and remembering the meaning of aparticular color which is intended to indicate a particular date of use.It is generally complicated and often inaccurate when relying on anindirect inventorying method to determine when a particular perishableitem should or should not be used.

Inventorying methods do not integrate the time and temperature historyof a particular item.

Desirably a device capable of accurately indicating the time andtemperature history of a perishable product would find practical use ifthe device could be initiated for monitoring precisely at the time whenthe perishable product is to be stored in preparation for serving in acoming period. The initiation process should be able to be initiated atthe time intended and not well in advance of use. Advance preparationand initiation of such a device may defeat the utility since a means tostore such a device may lead to questions about the very questions thatthe device is intended to monitor.

It is of particular interest to provide a continuum of answers as to thestorage and treatment of perishable products. Perishable items typicallyundergo exposure to various temperature and other storage conditions aswell as changes in temperature during preparation, cooking, cooling, andsubsequent storage. It is often desirable to monitor and determine thecondition of a particular perishable item for food safety, palatability,thoroughness of cooking, and integrity during subsequent storage.Indicators capable of following and reporting the conditions ofperishables during the continuum of conditions provide a variety ofadvantages over devices, thermometers, discrete monitoring or the likewhich are only capable of reporting one parameter of a condition which aperishable item is exposed to.

Ideally, a simple indicating device capable of a plurality of monitoringcapabilities should be simple to use, accurate to interpret and provideonly a minimal incremental expense to the overall cost of the perishableitem to be monitored.

SUMMARY OF THE INVENTION

Plural intrinsic expiration initiation application indicators areprovided comprising an initiation means in which a soluble unreactedcomposition is applied to a substrate surface and is capable ofmonitoring/indicating multiple sequential or simultaneous processes.Initiation of the indication process is achieved by evaporation of asolvent and formation of a solid phase of the unreacted composition.When the composition forms a solid, it is intrinsically reactive to itsthermal environment resulting in polymerization and subsequent colorformation that can measure environmental parameters. The degree of colorformation and the intrinsic color hue is a function of the temperatureenvironment to which the substrate and indicating means are subjected.The degree of color formation and color hue can be calibrated to both aschedule for expiration and to have the plural ability to indicateenvironmental exposed temperatures. Subsequent environmental conditionscan be monitored wherein the device can further change color in responseto a plurality of differential environmental conditions an item isexposed to. Various substrates, formats and devices for delivering thesoluble unreacted composition may be employed for a variety ofsituations requiring monitoring of expiration of an item of interest.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a label of the present invention designating a food of thetype having an expiration of three days from date of receipt when storedin a refrigerator.

FIG. 1B shows the label of FIG. 1A after three days when the food hasexpired.

FIG. 1C shows the label of FIG. 1A indicating that the food has expiredafter three days and has further perished by exposure and equilibrium toroom temperature.

FIGS. 2A-2C show labels of the present invention, as described in FIGS.1A-1C, which designates the monitoring and indication of both foodproduct expiration and cooking.

FIG. 3A shows an alternative label of the present invention designed tomonitor and designate initial perishability, cooking, completion, andpost cooking perishability.

FIG. 3B shows the label of FIG. 3A at day three of storage.

FIG. 3C shows the label of FIG. 3A after three days of storage and thencomplete cooking.

FIG. 3D shows the label of FIG. 2A after three days of storage, completecooking, and three days of post cooking storage.

FIGS. 4A, 4B, 4C and 4D show a label prepared in accordance with thepresent invention and showing color changes of various portions thereofin response to time-temperature and temperature factors.

FIGS. 5A, 5B, 5C and 5D show a laminated label embodiment and showingcolor changes of various portions thereof in response totime-temperature and temperature factors.

FIGS. 6A, 6B, 6C and 6D show another embodiment of label utilizing a barcode with individual bars of the code printed with varioustime-temperature and temperature indicators.

PLURAL INTRINSIC EXPIRATION INDICATION CHEMISTRIES

Plural intrinsic expiration indication chemistries involve the processof transforming a formulation from an inactive form to an activated format a specific time desired. Materials which can be transformed from aninactive soluble form to an active insoluble form are desirable sincetheir state from solution state to a solid state can serve as anactivating process. Further, it is desirable to utilize a compositionwhich is able to initiate a coloration process once the composition hastransitioned to a solid crystalline form. It is also important that thecoloration process is sensitive to the environmental temperature towhich the crystalline composition is exposed to where the compositionaccelerates in coloration at increased temperatures and decelerates incoloration at reduced temperatures. Importantly, it is desirable for thecolorization hue to change with absolute temperature that thecomposition is being exposed to. For example, an indicator can have aplurality of sensing applications if it both becomes colored with timeand subsequently changes color from one hue to another depending on theabsolute temperature of exposure.

Diacetylenic compositions have the advantage of coloration in the solidcrystalline state through a topochemical polymerization reaction yetremaining stable and uncolored in a dissolved solution state.Diacetylenic monomeric materials can be made soluble in organicsolvents. Solution-based diacetylenic monomers can formmicro-crystalline films when deposited on a substrate. Application ofmonomeric solvent solution, containing a diacetylenic monomer, on asubstrate leads to the rapid evaporation of the solvent carrier. Thesolvent evaporation process yields a micro-crystalline film of thediacetylenic monomer on the substrate.

The resulting micro-crystalline layer of the diacetylenic monomer on thesubstrate surface renders the monomer in a physical form capable ofbeing cross linked through topochemical polymerization of the individualmonomer molecules in the crystalline lattice. The diyne structure of onemonomer can form a bond with an adjacent monomer through a 1, 4addition. The reaction leads to a continued polymerization process whichforms a conjugated ene-yne structure. The ene-yne structure is colored.

Diacetylenic materials in a crystalline state have the advantage ofthermally annealing and polymerizing to form a colored entity. Thedegree of polymerization and subsequent color relates to the time andtemperature the diacetylenic crystals are exposed to. Thermalpolymerization in diacetylenic compositions to the coloredpolydiacetylenic form can be accomplished at a variety of relevanttemperatures. The diacetylenic composition can be selected for thermalannealing and polymerization at below freezing temperatures, in therange of freezing temperatures, at common refrigerator temperatures (35°F.-55° F.), and above refrigerator temperatures.

For a given application, the molecular structure of a diacetylenicmonomer will be selected based on how the structure will respond withinthe range of coloration intensities generated during the polymerizationprocess, the time frame it takes for coloration to occur, thetemperature at which the coloration is intended to occur and anyintended pluralities of monitoring functions the intrinsic expirationinitiation indicator is intended to have.

Diacetylenic monomers can be symmetric or asymmetric in structure. Thekey criteria for selecting a particular diacetylenic monomer as a pluralintrinsic expiration initiation indicator is that it will become coloredunder the conditions and timing necessary to accurately profile the timeand temperature exposure of interest. The monomer can come in the formof a straight chain aliphatic carbon chain, a single chain lipid, asymmetric bis compound, a dual chain molecule, a linear or branchedcompound, have aromatic or non-aromatic groups, have carbamate groups,carbonyl groups, ester linkages, amide linkages, polyethylene orpolypropylene linkages, bridging groups, peptide linkages, azidelinkages, thiol linkages, carbohydrate linkages, phosphate linkages orthe like.

Thermochromically reversible compounds can be prepared by the additionof groups which strongly hydrogen bond intermolecularly. For example,amide linkages have the advantage of promoting stable crystal formationas well as strong intermolecular hydrogen bond formation which promotesthermochromic reversibility. Amide linkages on the monomeric compoundassist in the preparation and utility of plural applications where it isimportant to measure both a time/temperature parameter for perishabilitythrough color generation as well as absolute temperature, both at lowtemperatures as well as reversibility to measure high temperatures.

Ester linkages promote irreversibility since esters do not significantlyhydrogen bond. Non-hydrogen bonding systems have the advantage ofirreversible coloration during the time/temperature monitoring processand subsequent irreversible coloration during a second plural monitoringevent such as a higher temperature irreversible temperature triggeringevent.

Symmetric bis-alcoholic groups can be used to prepare plural intrinsicexpiration indicators which become colored during the time/temperaturemonitoring process and subsequently can irreversibly change color from ablue color to a bright orange color either from complete hydration orexposure to temperatures above room temperature. For example,4,6-deca-1,10 diol will thermally anneal at refrigerator temperature asa time/temperature indicator and irreversibly change color form a blueto orange color upon complete hydration.

Hydrocarbon chain lengths can be adjusted to expand pluralityapplications and to adjust the coloration process duringtime/temperature monitoring. For example, short chain compoundsincluding 5,7-dodecadiynoic acid, 5,7-tetradecadiynoic acid, or5,7-hexadecadiynoic acid may be used without further modification or befurther modified. In either case, the low melting transitions of thesecompounds permit activation at low temperature in a crystalline statewhereas maintaining these compounds above their melting transition stateprevents crystallization and therefore prevents thermal polymerization.Modification of these compounds to amide forms can both promotethermochromic reversibility and increase the melting transition.

Longer chain compounds with chain lengths from 18 carbons to 30 carbonscan significantly increase the melting transition of the pluralintrinsic expiration indicator and thereby be applied to a combinationof time/temperature indication and plural applications such as colorchanges indicating safe cooking temperatures.

Medium chain length carboxylic acid derivatives such as 10,12tricosadiynoic acid and 10,12-pentacosadiynoic acid used as pluralintrinsic expiration indicating materials have the combined property ofbecoming colored with time and temperature, but at a dramaticallyreduced rate. Therefore, compounds such as these have the advantage ofserving as long term monitoring materials. For example, they may becomecolored over periods of weeks or months rather than days. In addition,compounds such as these will change color thermochromically at differentelevated temperatures depending on the degree of polymerizationachieved. Low levels of polymerization and coloration will result incompositions which turn from a blue form to a red form at temperaturesin the range of 100° F. to 130° F. Increasing levels of polymerizationlead to a thermochromic color tradition of between 130° F. and 150° F.Yet higher levels of polymerization to a dark black blue hue can lead toa thermochromic color tradition above 150° F. Compositions such as 10,12tricosadiynoic acid and 10,12-pentacosadiynoic acid provide for thedevelopment of plural intrinsic expiration indicating devices whichmeasure time and temperature and subsequently indicate increasingtemperature exposure levels for cooking or preparation.

Chemical Doping and Initiation Enhancers

Diacetylenic monomers of a specific chemistry can be doped with traceamounts of a similar co-crystallizing diacetylenic monomer. The processof doping trace amounts of a compound can effect the time/temperaturesensitivity of the final composition. For example, trace amounts of adoping agent in the range of 1-10% of an 18 carbon chain diacetyleniccompound can be admixed into a pure composition of a 16 carbon chaindiacetylenic compound. The doping process can provide defect structureswithin the final crystal matrix. Defect structures can facilitatepolymer formation by providing flexibility within the crystal lattice. Aresulting admixed or doped crystal may more rapidly or more sensitivelycrystallize compared to an undoped crystal lattice.

Doping compounds can be added to a pure diacetylenic composition from50% to 0.001% by weight. Usually, doping compounds are added frombetween 25% to 0.01% and more usually between 15% and 0.1%. Typicallydoping compounds are added between 10% and 1% by weight. The dopingcompound added will depend on the monomeric diacetylenic compoundselected as the plural intrinsic expiration indicating molecule.

Usually the doping compound or agent will itself be a similardiacetylenic compound, however may also be a compatible organic compoundwhich may effect the formation and sensitivity of the resultingpolydiacetylenic polymerization reaction. Usually the doping compoundwill differ from the dominant monomer by not more then 10 carbon atoms.More usually the doping compound will differ from the dominant monomerby not more than 5 carbon atoms and typically by only 2′ carbon atoms.For example, 10,12-pentacosa diynoic acid can be doped into a pureformulation of 10,12-tricosa-diynoic acid to enhance its sensitivity tothermal annealing.

Doping compounds can be added to the final plural intrinsic indicatingcomposition at any of a number of steps or elements of the indicatingdevice. The doping material may be added into the carrier solvent to beapplied to a substrate. The doping material may be impregnated into thesubstrate itself during the processing and preparation of the substrate.Alternatively, the doping material may be added to an ink compositionused for coloration of the background at the location where theintrinsic expiration indication material is intended to be applied.

Promotion of the initiation process also can be accomplished by physicaland chemical means which may be used to enhance the time temperaturecoloration process. Sensitizing chemicals, polymerization enhancers, andinducing agents can be employed to impact the coloration process.Enhancers or modulators can be used to speed up the coloration processor slow down the process. For example, low levels of light may beemployed to modulate or accelerate the coloration process. Although thecoloration process can take place in the absence of external lightinduced polymerization in monomer crystals, the presence of low levelsof ultraviolet light (254 nm peak bandwidth) can significantlyaccelerate the coloration time and dramatically reduce the time framefor monitoring a particular perishable object.

Metal salt forms of plural intrinsic expiration indicating materials inmonomeric forms can be utilized to modulate sensitivity. Compatiblecounter ions to carboxylic acids or amines can be used to sensitize ordesensitize the completion to coloration over a time and temperatureprofile exposure. For example, cadmium, calcium, sodium or other ionscan be used to form salts. Other metals can be used to participate inthe polymerization process as augmentors such as platinum or other rareor common metals. Pure or mixed metals can also be used.

Carrier Solvents

Solvents used for solubilizing, dispersing, spreading and evaporating toleave behind the monomer as a plural intrinsic expiration indicationmaterial are selected based on their effectiveness at forming a finalmonomer micro-crystalline film. The choice of solvents can effect thetype of monomer crystals formed, the crystal integrity andpolymerizability of the monomeric material.

Certain solvents promote rapid dispersive crystallization of the monomerand yield an application mark which is active within the desirable rangeof time/temperature indication intended. For example, ethanol andchloroform solvents either alone or in mixtures serve as compatiblesolvents. Methanol and acetone tend to be poor spreading solvents sincemonomeric diacetylenic compounds tend to form poor crystals upon solventevaporation.

Volatile solvents which can be used to dissolve and disperse the monomeronto a substrate include: ethanol, chloroform, dichloromethane, carbontetrachloride, terpenes, ethers, propanes, ethyl acetate, hexane,hexanes, acetonitrile, combinations of solvents, benzene, isopropanol;methanol, butane, isobutanol, glycol, methylethylketone, low temperaturepolyethylene glycols, polar and apolar solvents, and the like.

Combinations of solvents may be used to modulate the solvent evaporationprocess. Solvents in which the monomer is highly soluble may be used inmixtures with solvents in which the monomer is less soluble. A balanceof solvent concentrations may be used where the evaporation rate of thehighly soluble solvent exceeds the evaporation rate of a less solublesolvent. The concentration balance changes between the differentsolvents can be used to influence the monomer crystallization processduring application of an ink to a substrate. Mixed solvent systems canbe used to increase or decrease sensitivity of the plural intrinsicexpiration initiation indication system.

Carrier Ink Compositions

Carrier ink compositions include a solvent for solvating andsolubilizing the monomer and a concentration of the monomer practicalfor application to a substrate. Generally, concentrations of monomerrange from 500 mg/ml to 10 mg/ml, more usually from 300 mg/ml to 25mg/ml, and typically from 200 to 50 mg/ml.

High monomer concentrations can be used to increase the rapidity ofcolor development and shorten the time exposure profile. Low monomerconcentrations can be used to increase the time for color developmentand prolong the exposure profile. The concentration of the pluralintrinsic expiration initiation indicating material can be adjusted incombination with the substrate porosity and background stationary ink tocalibrate the intended time/temperature profile intended for aparticular perishable application.

Carrier ink compositions can be formulated to include inactive agentssuch as thickening materials, coating materials, protective materialsand the like. The type and grade of additional inactive agents selectedwill depend on the particular need required by a product application.For example, for extremely high sensitivity applications where it isimportant for the intrinsic indicating material to become colored withina short period of time, a thickening agent may be desirable to includesince the thickening agent can facilitate the application of thicklayers of the intrinsic indicating monomer. The thickening agentpromotes increase concentrations of monomer to be applied, therebyincreasing the color appearance during a shorter time frame.

Inactive agents are generally added at concentrations where they are ofuse. The inactive agent concentration generally ranges from 1000 mg/mlto 0.1 mg/ml, more usually from 500 mg/ml to 1 mg/ml, usually from 250mg/ml to 5 mg/ml and typically from 200 mg/ml: to 10 mg/ml. It isparticularly important to select a thickening agent which does notinterfere with the physical and chemical properties of the pluralintrinsic expiration initiation monomer, its crystallization properties,or polymer formation from the diacetylenic monomer to polydiacetylenicpolymer.

Examples of inactive agents include polyethylene glycols, polypropyleneglycols, carbohydrates, cellulosic materials such as nitrocellulose andmethyl cellulose, inert plastics such as acrylics, styrenes,methacrylates or the like, micro-plastic beads used for gel and ballpoint inks, emulsifiers such a lecithin, lipids and polymeric lipids andother inactive agents typically used as thickening agents.

Application Substrate Surface Characteristics

The monomer solution can be applied to any of a variety of surfaces. Thesurface should be clean, uniform, have a coloration which providescontrast compared with deposited monomer that converts to a coloredtime/temperature indicating polymer, and should be free of anycomponents which could negatively impact the monomer from forming amicro-crystalline coating or from converting to a colored polymer underthe conditions intended for time/temperature indication.

More porous surfaces have the advantage of accumulating larger amountsof monomer solution whereas less porous surfaces may accept smalleramounts of monomer solution during the application process. Varioussubstrates may be treated in a particular way either chemically orphysically to be more or less porous. For example, papers can, be madewith an open fiber to increase porosity whereas they can be treated witha varnish to reduce porosity. Plastics can be plasma irradiated toincrease porosity or heat treated and annealed to reduce porosity.Metals may be chemically etched to increase porosity and polished toreduce porosity. The degree to which a substrate is treated to increaseor decrease porosity will depend on the application of interest and theintended sensitivity of the plural intrinsic expiration initiationindicator.

Substrate surfaces utilized for spreading the monomer solution on areselected based upon their properties for final monomer micro-crystalformation. The surface should assist in the, uniform formation ofmicro-crystallization of the monomer. Porous surfaces attract increasinglevels of monomer solution thereby compartmentalizing more monomer percross-sectional area.

Application Substrates

A wide range of substrates for application of the intrinsic indicatingmaterial can be employed. The substrate type selected will depend on theimplementation and specific product embodiment utilized for theintrinsic indicating material. Substrates may be used as an attachmentto a food container or the container itself. The container may besingle-use such as a bag or multi-use such as a plastic container orstorage pan. An attachment substrate can be an adhesive, label or otheritem which can be put in contact with a food storage container.

The substrate may be flexible or rigid depending on the intendedapplication. The substrate may also be permanent or disposableimmediately after use. For example, it may be desirable for certainapplications that the substrate be permanently affixed to a containerand the substrate be used repeatedly with the same plural intrinsicexpiration initiation marker. Alternatively, it may be desirable forother applications that the substrate be single used and disposablewhere the substrate is affixed to a single use container such as a delidish.

Substrates are selected for their ability to beneficially interact withthe intrinsic indicating material, its compatibility with food storageconditions, its compatibility with a food storage container and otherproperties such as visibility, opacity and porosity amenable tovisualizing the color development of the intrinsic indication material.

Substrate material compositions can include, but are not limited to,papers, cardboard, plastics, metals, alloys, glass, wood, ceramics,printed inks, paint, foils, extruded surfaces, wax, carbohydratematerial, cellulosic material, sintered surfaces, lacquers, cloth,adhesives materials, glues, epoxy resins, polymer resins, heat sinkmaterials, solder, thermoforming materials, medical substrates, rubber,vinyl materials, silicon rubber compounds, various polymer basedcomposites, and a variety of other compatible materials which can serveas suitable substrates or matrices for the plural intrinsic expirationinitiation indicating materials.

Substrates can be rigid or flexible depending on the intendedapplication of interest. For example, a flexible substrate such aspainted surface has application to a storage bag where the perishablefood is stored. A rigid substrate has application to a rigid storagecontainer where the storage container has a compartment for inserting aplastic tab where the plastic tab is the rigid substrate for applyingthe intrinsic indication material.

The substrate can also be a liquid where the intrinsic indicatingmaterial is admixed from a solubilizing solution and precipitated ormicro-crystallized with a precipitating solvent. Blending of the solublesolution containing the monomer with the precipitating solvent at timezero will cause an immediate precipitation or crystallizing process andinitiate the time/temperature indicating process.

Substrates and/or items to be marked with the intrinsic indicatingmaterial include but are not limited to: label material which dissolvesin water such as that sold by DayMark Food Safety Systems Inc. under thetrademark DISSOLVE-A-WAY®, standard printable commercially availablelabel materials such as paper and plastic, plastic tapes, paper tapes,cloth tapes, freezer tapes, transparent films, paper tags, name tags,clips with name tags, aluminum foil, shrink wrap material, plastic bags,printed plastic bags, sintered surfaces, standard and treated paper,plastic card stock, miscible solvents such as water, cotton cloth,various textile fabrics, mesh materials, wrapping films, butcher paper,butcher tapes and, sealing materials, printed ink labels, painted zone,pressure sensitive strips, rubber bands, heat sink materials, packagingmaterial, plastic pans, metal pans, glass dishes, paper boxes includingcardboard boxes, bandages, Tyek brand extruded packaging material, woodimplements, cheese cloth, medical substrates including medicaldiagnostic paper test strips, tracing paper, acetate surfaces, plaincolored paper Post-it brand notes (3M Company), plain and coloredPost-it brand plastic Flags (3M Company), tape tabs and the like.

Substrate Additives

Substrates can also be formulated with added nucleation sites to enhancethe micro-crystal nucleation process. Adding micro-crystal nucleatormaterials has the added benefit of overcoming inconsistencies in anormally non-uniform substrate. Good nucleating materials can beinsoluble in the solvent used to carry the monomeric indicatingmaterial.

Nucleating materials include micro-particulate powders such assilicones, talc powders, fine grain fibers, dye powders including rawcolorants for plastics and papers, filtration materials such aschromatography materials, organic and inorganic materials, mineralpowders, titanium dioxide powder, starch powders, ceramic powders,insoluble clear plastic resin powders, polyethylene glycols,polypropylene glycols and the like. Alternatively, the nucleationmaterial can be added at final concentration relative to the carriersolvent employed. Generally, concentrations of nucleating enhancer canrange from 1000 mg/ml to 1 mg/ml, usually from 500 mg/ml to 5 mg/ml, andtypically from 250 to 10 mg/ml and more usually from 100 to 25 mg/ml.

The nucleating material can be added directly to the substrate duringsubstrate formulation or can be added to the carrier solvent and monomercomposition and delivered to the substrate during the, process ofmarking the indication material to the substrate.

The nucleating material can be imprinted on a substrate as a part of theimprinting process used to create a background color on the substrate ofinterest. For example, the nucleation material can be formulated with anink which is used to create a background reference color.

Contrast Colors and Backgrounds

Stationary non-changing colors can be added to the solvent carrying theinitiation monomer. The color serves the purpose of indicating where theinitiation monomer is being applied. Additional colors may also be usedto reduce the risk of misinterpretation in the event that the initiationmonomer pen is dry at the time of use. The presence of a stationarycolor will help the user identify that the pen is working properly. Thehue, intensity, contrast or other printing parameters can be adjusted tocalibrate the intended contrast of the color developed by the intrinsicexpiration indication material.

Background stationary color hues can be adjusted to prolong the apparentcolor development of the plural intrinsic expiration indicator. Forexample, if the plural intrinsic expiration indicating material becomesdark purple-blue at refrigerator temperatures, backgrounds with reds,magentas, purple, and blues tend to blend in with the indicator andprolong the apparent time to expiration. Backgrounds with yellow andgreen hues tend to provide higher contrast in combination with ablue-tinted indicating material tending to reduce the apparent time toexpiration.

Background stationary colors can be any compatible or complimentarycolor with the color change produced from the intrinsic indicatingmaterial. Colored backgrounds can be created using standard printingmethods such as off-set, ink jet, rotary letter press, flexography, padprinting, spraying, photographic, thermal imprinting, and any variety ofprinting processes which yield a surface compatible with the depositionand activity of the intrinsic indicating material.

Pre-colored/polymerized plural intrinsic expiration indicating materialscan be pre-coated on a substrate and serve as the reference backgroundfor marking with a solvent soluble monomeric intrinsic indicator. Thisprocess has the advantage that the solvent in the application device canimmediately trigger a color change in the pre-colored/polymerizedbackground indicating that the application device is charged with thesolvent solution and is not dried out. In addition, the solvent/monomersolution delivered to the substrate surface will be easily located onthe background by triggered mark. As the time/temperature processensues, the expiration indication can be visualized by a color change inthe mark. The mark will change color over time and depending ontemperature to become the same color as the original backgroundpre-colored/polymer. The background color can be calibrated and used asa reference color for indicating what the final color of the indicatorshould be in order to indicate when an attached item is perished.

Printing methods can be used to encode reference colors which provide areference coloration as to subsequent environmental exposure conditionsthat may be indicated by the plural intrinsic expiration applicationdevice. For example, where colored backgrounds may be used to enhancethe contrast of the color development process that the plural indicatorgenerates during a time/temperature profile, stationary printed colorssuch as a orange/yellow can be pre-printed in a location as to provide acolor reference as to what the final color will be if the indicatingmaterial is heated to a selected temperature for cooking as an example.

Printing processes and commercial printing inks can be further utilizedin combination with porous substrates to regulate the permeability ofthe porous substrate and provide a color contrast to the finalcoloration of the plural intrinsic expiration initiation material as thecolor develops during an application. Dot gain, dot size, dot shape, dotcoloration, and percent coverage of a pre-printed area can be used toregulate the amount of plural intrinsic expiration initiation materialdelivered to the porous substrate.

Commercial printing inks can be highly, impermeable, moderatelypermeable, or permeable to the plural intrinsic expiration initiationink. Impermeable commercial printing inks can be used in formats wherethe printed zone or area resists permeation of the plural intrinsicexpiration initiation ink. For example, dot patterns in various percentcoverage can be used to adjust the permeation of the plural intrinsicexpiration initiation material. During application of the pluralintrinsic expiration initiation ink, the ink will be absorbed into aporous substrate and incorporated around the ink zone. The ink zone canact as a barrier region where on the surface little or no ink willdeposit. The pre-printed ink zones can serve to effectively concentratethe plural intrinsic expiration initiation material in the porous areasbetween the pre-printed zones. In addition, the coloration of thepre-printed area can be adjusted to match or contrast the finalcoloration of the plural intrinsic expiration initiation material.

Pre-printed regions can have coverages from 0.1% to 100%. More usuallypre-printed coverage will range from 0.5% to 90%. Typically coveragewill range from 1% to 70%. The range of coverage will depend on theperishable application of interest. The printed dot size can range from0.001 millimeter to 1 millimeter and typically from 0.01 millimeter to0.1 millimeter. Multiple side-by-side printed zones with pre-adjustedpercent coverages find use in applications where the plural intrinsicexpiration initiation device can have multiple choices of expirationperiods.

The side-by-side format permits the selection of a particular expirationperiod. For example, 7 zones each representing 7 sequential days of acalendar week can be printed with varying percentages of pre-printedimpermeable ink. The ink hue can match the final coloration of nativeplural intrinsic expiration initiation material during coloration. Whena particular weekday is marked for anticipated expiration with an inkcontaining the plural intrinsic expiration initiation material,coloration will proceed such that the region marked will accuratelyindicate expiration on the anticipated day.

Application Delivery Systems

A wide range of application delivery systems may be used for applyingthe solvent solubilized monomeric solution depending on the amenableapplication process. Application delivery process can utilize a simplemanual process such as a felt tip pen filled with a soluble inkcomposition containing the monomeric plural intrinsic initiationindicating material for marking. Alternatively, an electronic applicatordevice can be employed which has a reservoir of ink and prints the inkautomatically on dispensed labels or bags on demand. In each case, theprinting or application process initiates the time/temperaturemeasurement process since the process requires solvent application ofthe monomer to a substrate.

Delivery processes can include: in-line printers, piezo-electric ink jetprinters, bubble jet printers, commercial ink jet printers, off-setprinters, flexographic printers, drum printers, pad printers, ink pads,markers, stamps, stampers, compartmentalized solvent water systems, felttips, sponge, adhesive removal, dissolve, liquid dispensers, fingerpaints, self inking stamp, rubber stamp, wipe-ons, pans, pencils,crayons, ball point pens, electronic stampers, scratch-off for release,liquid gel caps, stencil applicators, balm applicators, liquid tubeapplicators, spray ons, roll ons, rub ons and the like.

Containers with Foods/Beverages

Food and other perishable products may be stored at refrigeratortemperature in any of a variety of containers suitable for a particularorganization. Plural intrinsic expiration initiation indicators can beapplied to a container in a form or format compatible with thecontainer. For surfaces on a reusable container, it is desirable to usean indicator which can be applied for monitoring during a particularperiod. Labels are desirable since they can be applied directly to apan, tub, box or other compatible surface for usage during a specifiedperiod.

Containers can include: boxes, pans, tubs, plastic bags sacks, jars,cans, paper wraps (meat paper/butcher paper), milk bottles, blood bags,racks, drums, cartons such as egg cartons, hermetically-sealed bags,liquid dispensers, packets, pouches, envelopes, vegetable bags, storagecontainers, tags, hock locks, tape, thermoses, sperm bank containers,tubes, pharmaceutical drug containers wire labels, aluminum foil wraps,plastic wraps, styrofoam trays, and canisters or the like.

In particular, a variety of different plastic bag materials,compositions, shapes, colors, designs or the like can be used as storagecontainers for perishables and are compatible with plural intrinsicexpiration indicators. Bags can be used for a singular purpose such asstorage of specific food proportions. Storage bags are typically madewith polyethylene or polypropylene. Bags can be used for multiplepurposes such as storage and cooking. For example, polyester and nylonbags can be used to both store meat and withstand the temperaturesnecessary for cooking.

Bags can be imprinted with a fluid ink where the imprint can serve asthe substrate for marking with the plural intrinsic expirationindicator. Alternatively, a label pre-printed with appropriate graphics,may be adhered to the bag and used as the substrate for applying theplural intrinsic expiration indicator. In either case, plastic bagsserve as an attractive disposable container for utilizing an applicationform of the plural intrinsic expiration indicator.

For containers that will be washed subsequent to the food storageperiod, it is desirable to use plural intrinsic expiration initiationindicator as the substrate for the labels which dissolve in water and/ordetergent or soap such as the previously reference DISSOLVE-A-WAY®labels. Labels which dissolve permit the easy application of theindicator to a container and easy removal of the label during thecleansing process for cleaning the container.

Visual Output

The visual output resulting from the color formation caused by theplural intrinsic expiration initiation indicator can range from a simplemark or line to a more complex message or graphic. For example, a simplemark, check or strike can be made using a felt tip pen as the deliverymethod for applying the material. A mark can be combined with astationary visual graphic printed on the intended substrate. For examplea partial warning sign can be graphically printed on a substrate using acontrast ink base. The intrinsic expiration initiation indicatingmaterial can be marked on the graphic in such a manner as to completethe visual graphic once the indicating material has changed color.

As an illustration, a printed color circle with a round darkened bordercan serve as the initial graphic. The intrinsic material can be markeddiagonally across the center of the circle. After color generation fromthe intrinsic material, the final resulting graphic intended to indicateexpiration can show a round circle with a line through it. A“cross-through” circle has the generic connotation that something shouldnot be used or should not be handled. Combining symbolism with the useof the plural intrinsic expiration indicator has the advantage ofreinforcing that a particular item has perished and should no longer beused.

A variety of other symbolic means, messages or the like can be utilizedincluding: the integration of bar codes, graphics, numbers, letterwords, marks, lines, visuals, pictures, stamp imprints, line art,graphic compilations, symbols, warning emblems, holographic diagram,block diagrams, dock, fluorescence output, black light patterns,fill-in/threshold diagram, obscuring message, revealing message, grids,lines, patterns, textures as well as a variety of other graphic means.

Applications

The plural intrinsic expiration initiation indicator can be used in foodservice, restaurant, hospital, blood banking, shipping and distribution,recreational and outdoors activities, theme parks, fairs, school lunchprograms, commercial, institutional, medical, consumer home-use,educational, industrial, agricultural, dairy, and other relevant areasof applications where a product or item of interest should beperiodically monitored for expiration. Perishable items and items whichchange their characteristics over time may be monitored using theindicator.

Specific examples of perishable products which should be periodicallymonitored and have utility for plural intrinsic expiration initiationindicators include: foods including raw meats, mail and email ordermeats and perishables, raw poultry, bulk uncooked hamburger andhamburger patties, raw fish, sausage, once cooked items, lunch meats,cheese, children's consumables such as Lunchables (Kraft Corp.),consumer home use repackaged perishables such as hot dogs, fast foodserved, Chinese food, Mexican food, sushi, cookie dough, perishableliquid beverages such as milk and cream, coffee, butter, condiments,wines, beverages, fresh and frozen foods, ice cream, raw cookie dough,thawed foods such as previously frozen pancakes or waffles, tofu, eggs,photographic films and papers, cigars, cosmetics, pharmaceutical andmedicinal products, stored blood, sperm in sperm banks, stem cells,fertile and non-fertile eggs, tissues in hospitals or tissue banks,tissue cultures, bacterial cultures, DNA samples, transplantationorgans, sensitive chemicals, fine reagents, airline service foods,leftovers, baby formulas, stored mothers milk, post sterilized products,diagnostic devices, perishable products with broken seals, materialswith half-lives, agricultural products such as seeds, germ cells, lightsensitive materials, toxic perishable waste in urgent need of treatment;compositions which may undergo flavor loss, home-use water filterexchange, and the like.

Plurality Applications (Permutations)

The plural intrinsic initiating expiration initiation indicator can beused in a singular format to report one element of an expiration processor be used in a tandem fashion where the indicator reports or monitorsthe progress of one or more processes. The indicating mechanism,composition, substrate, formulation, algorithm and other ancillaryqualities can be adjusted according to the type of application theindicator is intended to be used for.

A continuum of application for a particular plural intrinsic initiationexpiration indicator can be accomplished by selecting a compositionwhich undergoes multiple color change events. Plural intrinsicindicators provide for more than one sequential or simultaneousindications arising from of a single detection device. For example, anindicator can be used to monitor the perishability of foods byindicating a color formation over time and temperature whilesimultaneously indicating the absolute temperature of the environmentthat the food has been raised or lowered by the color hue that theindicator changes to.

In another example, a plural indicator can monitor perishability offoods by indicating a color formation over time and temperature whilealso indicating the degree of humidity that the indicator is exposed to.Thermally polymerizable material compositions of diacetlyenic monomercan be employed that develop color with time and temperature andsubsequently change to another color upon hydration due to humidity orexposure to bulk water.

A variety of singular through plural indication parameters can besimultaneously or sequentially monitored using a plural intrinsicexpiration initiation monitor including examples such as: time-reducedtemperatures, time-varying temperatures, time-elevated temperatures,time/temperature storage combined with subsequent hot holdingtemperature, time/temperature storage combined with subsequent cookingtemperature, time/temperature storage combined with subsequentsterilization temperature, time/temperature storage combined withsubsequent cooking temperature combined with further subsequentpost-cooking storage, short time/temperature combined with ultravioletirradiation sterilization, long time/temperature combined withdishwasher safety temperature achievement, time/temperature storagecombined with irreversible elevated temperature monitoring, hightemperature storage maintenance combined with revisable temperaturecooling, prolonged ultra-low temperature storage combined with shorttime elevated temperature exposure, time/temperature storage combinedwith humidity exposure at elevated temperatures, time/temperaturestorage combined with hydration submersion, and a variety of other time,temperature, temperature cycling, irradiation, hydration, and otherenvironmental exposure conditions and the like.

EXAMPLES

Solvent based ink formulation: An ethanol/dicholormethane inkformulation was prepared using a solvent composition containing absoluteethanol. (Aldrich Chemicals) to dichloromethane (Aldrich Chemicals) 5 to1 by volume. N-ethanol-hexadeca-5,7-diyneamide. (prepared synthetically)was dissolved in ethanol to dichloromethane 5 to 1 by volume andfiltered through filter paper using gravity filtration (Whatman no. 541)to a final concentration of 200 mg/ml. The final solvent based inkformulation was clear and free of any particulate matter. The ink basewas tested for its color changing characteristics by application topaper and plastic surfaces. Ink marks, once dried, were exposed toultraviolet light (254 nm) for several seconds using a hand held lamp.The ink marks immediately turned a deep magenta color at roomtemperature. The ink base was used in filling a variety of printingdevices including pens, ink jet cartridges, stamps and the like.

Plural intrinsic expiration indicator felt tip ink pen applicator: Amonomer felt tip ink pen applicator was prepared using the solvent baseink formulation above. An empty felt tip pen body (DriMark Inc.) wasfilled using 200 mg/ml of the solvent ink formulation previouslydescribed. The ink formulation was stable at room temperature whenstored in the felt tip ink body. The pen was tested for writing on avariety of paper, plastic, printed, painted, metal, and other substratesurfaces. In each case, the substrates were tested for their porosityand contrast for color development. Surfaces were compared for inkpolymerization activity using exposure with ultraviolet light (254 nm)for several seconds using a hand held lamp. More porous surfaces such aspapers showed a high level of color formation, whereas less poroussurfaces such as metals and plastics showed less color development.

Plural intrinsic expiration indicator felt tip ink pen applicatorencoded with a stationary color background yellow: A monomer felt tipink pen applicator was prepared using the solvent base ink formulationabove. An empty felt tip pen body (DriMark Inc.) was filled using 200mg/ml of the solvent ink formulation previously described. The inkformulation was tinted yellow with a solvent based yellow ink. Theyellow ink was added to be used as a permanent yellow additive at aconcentration of 1 ml permanent yellow ink (Pantone yellow, Letraset,England) to 10 ml solvent ink formulation in order to indicate where theplural intrinsic expiration indicating material was being applied. Theink formulation was stable at room temperature when stored in the felttip ink body. The pen was tested for writing on a variety of paper,plastic, printed, painted, metal, and other substrate surfaces. In eachcase, the substrates were tested for their porosity and contrast forcolor development. Surfaces were compared for ink polymerizationactivity using exposure with ultraviolet light. (254 nm) for severalseconds using a hand held lamp. More porous surfaces such as papersshowed a high level of color formation whereas less porous surfaces suchas metals and plastics showed less color development.

The yellow additive had the advantage of indicating where the pluralintrinsic expiration initiation indication mark was placed and if theink pen dried out after prolonged use. The yellow additive caused ayellow mark to turn green at refrigerator temperature's in combinationwith blue color development of the plural intrinsic expirationinitiation material.

Printed DISSOLVE-A-WAY® labels for plural time/temperature andtemperature monitoring devices: 2 inch by 3 inch die cutDISSOLVE-A-WAY®labels were printed with visual graphics using an ink jetprinting system (Epson Stylus Color 3000, Epson Inc.). Instructionalinformation, naming information, graphic display and backgroundcoloration (blue hues) were printed within the label border. 5side-by-side circles (0.5 inch dia.) each with a circular outline weredisplayed from, clear background on the left with progressivelyincreasing blue tinted centers moving to the right hand circle. Thecircles were numbered 1 through 5 indicating which day from marking thelabel would indicate expiration. The label also contained a graphicreference as to what a user sees when label indicates expiration.

For use, the label was applied to a plastic pan containing perishableuncooked chicken pieces. The contents were expected to expire 3 daysafter purchase. The label was placed in a visible location on the sideof the pan. The third day (day 3) circle was marked diagonally with themonomer felt tip ink pen applicator containing the plural intrinsicinitiation expiration indicator (see example above “Plural intrinsicexpiration indicator felt tip ink pen applicator”). The mark was placedin the circle in direction consistent with the reference graphic. Thepan was placed, in a refrigerator and stored at 40° F. for several days.The refrigerator was opened and closed under a standard routine of use.The pan was removed from the refrigerator 2 times per day on day 1, 2,and 3 for 5 minutes per time. The diagonal mark through the day 3 circlebecame visible on the third day from application indicating that the pancontents had expired. The indicator mark also transitioned from a lightblue hue to a magenta hue once the pan had warmed to room temperaturefurther indicating that the contents had not only expired, but also werefurther perished by exposure and equilibration to room temperature.

The pan contents were disposed once the indicator registered expirationon day 3 from initiation. The pan was washed using a conventionaldishwasher during which time the DISSOLVE-A-WAY® label was dissolved asintended. All inks, the plural intrinsic initiation expirationindicating material, and adhesives were effectively removed andeliminated as intended during the washing process leaving behind a cleanpan for subsequent usage.

Referring to FIGS. 1A, 1B and 1C, there is shown a label generallydesignated by the numeral 10. The label 10 may be paper, a waterdissolvable material such as that sold by the Assignee of the presentpatent application under the mark DISSOLVE-A-WAY® and described in U.S.patent application Ser. No. 10/008,911 filed. Dec. 6, 2001 or any of anumber of plastics used as label materials such as low or high densitypolyethylene, VPC or PET. The label 10 had printed thereon fiveside-by-side circles, 11, 12, 13, 14 and 15 with a number printed aboveeach circle, namely, the number 1 appearing above circle 11, the number2 appearing above circle 12, the number 3 appearing above the circle 13,the number 4 appearing above the circle 14 and the number 5 appearingabove the circle 15. Displayed within the circular outline of circles12, 13, 14 and 15 was a background coloration in a blue hue or tint withincreasing degrees of tinting from a faint tinting in circle 12 andprogressively greater tinting in circle 13, more in circle 14 and thegreatest degree of tinting in circle 15 as represented by theincreasingly darker indications as indicated in FIGS. 1A, 1B and 1C.Circle 11 was displayed with a clear background.

Below the circles 1-5 is printing showing instructions to the user tomake a diagonal line 20 with the felt tip ink pen applicator containingthe plural intrinsic initiation expiration indicator monitor. Thediagonal line is to be made through only one of the circles, namely,that circle which represents the day when expiration of the food orother expiration-sensitive goods should be removed from service if notconsumed or used prior to such day. In FIG. 1A, the food contained in acontainer to which the label 10 was attached was of a type which wasgenerally recognized to have an expiration of three days from the dateof receipt at a restaurant or other consumer when stored in arefrigerator at temperatures on'the order of 45° F. Accordingly, circle13 was marked with a felt tip ink pen applicator containing a clearintrinsic initiation expiration indicator of the type previouslydescribed, for example, an ethanol/dicholormethane monomer. Since themonomer was clear, the mark in FIG. 1A extending diagonally in circle 13has been shown with dashed lines identified by the numeral 20.

If desired, a yellow additive may be incorporated into the monomerwhich, when applied to a circle having a blue tinted center will bevisible as a green color. The use of the yellow additive will clearlyconfirm to the user that circle 13 of label 10 has been marked with apen containing the plural intrinsic initiation expiration indicatormonomer.

In the lower right of the label 10 is another circle 16 smaller than thecircles 1-5 and containing therein a diagonal line 17 in a permanent,unchanging color indicating the color to which the diagonal line 20 ofFIG. 1A will appear when the food has expired. In the example shown, thediagonal line has turned to a blue hue after storage of three days at anominal temperature of 40°-45° F., being approximately the temperatureof the non-freezer portion of refrigerators. The blue hue is representedby the numeral 20A in FIG. 1B.

FIG. 1C is a representation in which the diagonal line formed by thefelt tip pen using the plural intrinsic initiation expiration indicatormonitor has changed to yet a different color, namely, magenta, after thegoods which had been removed from the refrigerator after three days andthen left at room temperature of approximately 70° F. The change incolor to magenta as indicated by the diagonal line 20B was an indicationthat the goods had further perished by exposure and equilibrium to roomtemperature.

Plurality device for time/temperature and 160° F. irreversible colorchange indicating subsequent cooking completion: Printed labels wereprepared to monitor and indicate both food product expiration andcooking. Printed labels were prepared similar as above. 2 inch by 3 inchdie cut labels were printed with visual graphics using an ink jetprinting system (Epson. Stylus Color 3000, Epson Inc.). Instructionalinformation, naming information, graphic display and backgroundcoloration (blue hues) were printed within the label border. 5side-by-side circles (0.5 inch dia.) each with a circular outline (0.1inch perimeter) were displayed from clear background on the left withprogressively increasing blue tinted centers moving to the right handcircle. The circles were numbered 1 through 5 indicating which day frommarking the label would indicate expiration.

The label was modified with a pre-printed square containing apre-polymerized zone with the polydiacetylenic polymer ofN-ethanol-hexadeca-5,7-diyneamide (prepared synthetically). Thepre-printed square turned blue when cold, magenta at room temperature,and irreversibly orange when elevated above 160° F. The pre-printedregion contained the same material as the material used as the pluralintrinsic initiation expiration indicating material.

The foregoing embodiment is illustrated in FIGS. 2A, 2B and 2C, wherethere is shown a label 30 prepared to monitor and indicate both foodproduct expiration and cooking. Similar to the embodiment of FIGS. 1A,1B and 1C, the label 30 had printed thereon five circles 31, 32, 33, 34and 35 representing the days. The circles 32, 33, 34 and 35 had printedtherein blue ranging from a light blue tint in circle 32 andincreasingly greater tint in circle 33, more in circle 34 to thegreatest amount of tint in circle 35. As in the previous embodiment, nocoloration was provided in the left circle, namely, circle 31. In thelower right corner of the label is a square 36 containing aprepolymerized zone with polydiacetylenic polymer ofN-ethyanol-hexadeca-5,7-diyneamide (prepared synthetically). Thepreprinted square 36 turned blue when cold, magenta at groom temperatureand irreversibly orange when elevated above 160° F.

Circle 33 was marked with a diagonal line 40 using the felt tip pen andthe plural intrinsic initiation expiration indicator monomer as in theembodiment of FIGS., 1A, 1B and 1C. The goods which were expected toexpire three days after purchase were removed from the refrigeratorafter two days and then cooked. Accordingly, the diagonal mark 40 whichwas marked in the circle 33 representing a day three expected expirationnever became visible. Accordingly, the diagonal line 40 is shown indashed lines.

The label 30 was applied to a combination storage, and microwave cookingbag. The bag was made with a polyester/polypropylene laminate and washeat sealed containing a meat marinade. The label 30 was marked as shownby diagonal line 40 in circle 33 for expiration on day 3 with a felt tippen applicator containing plural intrinsic expiration indicator. Thebag, containing an uncooked red meat marinade, was stored in arefrigerator and monitored twice per day each day after the label wasmarked. At day 2, the bag was removed and checked for perishability. Nodiagonal mark had yet appeared on the day 3 circle 33 indicating thatthe bag contents had not expired.

The bag and its contents were placed in a dish and cooked in aconventional microwave for 5 minutes. The pre-printed square 36 used forindicating cooking turned reversible from a magenta to an orange colorafter only 2 minutes of cooking. Since the color change indicatedreversibility from an orange color back to a magenta color, theindicator signaled that cooking was not complete. The bag and contents'were cooked 3 more minutes in the microwave oven and the indicator insquare 36 subsequently turned irreversibly orange indicating thatcooking was complete. The internal temperature of the red meat contentswas immediately measured to confirm that an internal temperature of themeat had achieved a temperature level of 160° F.

Plural indicators monitoring initial perishability, cooking completion,and post-cooking perishability: With reference to FIGS. 3A, 3B, 3C and3D, printed labels 50 were prepared and designed similar to thosedescribed above. Instructional material and designs were developed toaccommodate multiple usages including food perishability monitoring,cooking completion monitoring, and post cooking perishabilitymonitoring.

Graphics, were printed on the label 50 such that the plural intrinsicindicating material could be marked in a predetermined rectangle. Therectangle to be marked, rectangle 51, was bordered by three coloredreference rectangles 52, 53, 54. The left hand rectangle 52 was printedwith a medium blue tint representing what the indicator color will bewhen the plural intrinsic expiration indicating material changes colorto indicate that a perishable item must be cooked immediately. The upperrectangle 53 was pre-printed with a light orange tint representing whatthe indicator color will be when the plural intrinsic expirationindicating material changes to when the item is microwave cooked tocompletion. The right rectangle 54 was pre-printed to a purple huerepresenting what the indicator will be when the item is placed backinto the refrigerator, cooled to 35-40° F. and stored for several moredays.

The label 50 was applied to a combination storage and microwave cookingbag. The bag was made with a polyester/polypropylene laminate and washeat sealed containing a meat marinade. The label colors were calibratedsuch that it could be marked for expiration on day 3 of storage aspreviously described with a felt tip pen applicator (see example above:“Plural intrinsic expiration indicator felt tip ink pen applicator”).The bag, containing an uncooked red meat marinade, was stored in arefrigerator and monitored twice per day each day after the label wasmarked. At day 2, the bag was removed and checked for perishability. Themark in rectangle 51 had not yet turned to the reference color blueafter two days of refrigeration. On the day 3 of refrigeration, the markbecame the same blue hue as the reference color in rectangle 52 (seeFIG. 3B) indicating that the bag contents should be used immediately.

The bag and its contents were placed in a dish and cooked in aconventional microwave for 5 minutes. The marked rectangle 51 turnedreversible from a magenta to a orange color after only 2 minutes ofcooking. (See FIG. 3C). Since the color change indicated reversibilityfrom an orange color back to a magenta color, the indicator signaledthat cooking was not complete. The bag and contents were, cooked 3 moreminutes in the microwave oven and the marked square subsequently turnedirreversibly orange indicating that cooking was complete when comparedto the reference orange rectangle as shown in FIG. 3C. The internaltemperature of the red meat contents was immediately measured to confirman internal temperature of the meat had achieved a temperature level of160° F.

Immediately after cooking, the bag was placed in a refrigerator (35-40°F.). The marked center rectangle 51 was initially orange on the firstday. (See FIG. 3C). The marked rectangle gradually turned from an orangecolor to a purple color after continued refrigeration for 3 subsequentdays. (See FIG. 3D). On the third complete day of refrigeration, themark rectangle 51 had the same coloration and hue as the right handrectangle 54 indicating that bag contents, post cooking andrefrigeration should be consumed immediately or disposed.

Semi-automated label dispenser with internal marker for plural intrinsicexpiration indication: A semi-automated label dispenser for issuingpre-marked plural intrinsic expiration indicating labels wasconstructed. Labels with pre-printed graphics were prepare usingflexographic printing using a geometry and graphics described earlier.Rolls containing 250 die-cut labels were placed in a dispenser apparatuscontaining a digital counter, motorized dispenser, ink fluid reservoir,felt-tip pen applicator, a digital processing algorithm, a digitaldisplay, and a numeric key board.

The labels and semi-automated dispenser were registered such that when aday for expiration was typed in on the key pad, the dispenser wouldappropriately mark and dispense a label. The printing mechanism alsoincorporated the ability to print times and dates for activation on thelabel. Dispensed labels could be directly placed on a storage containercontaining a perishable product of interest. Labels were utilized asdescribed above and monitored for expiration of the food contents theywere used with.

Pre-portioned bags imprinted with graphics and substrate compatible withthe plural intrinsic expiration initiation indicator: Flexographic fluidinks (Fluid Ink Technology, Inc.) were used to print regions on plasticbags (treated or untreated polypropylene and polyethylene). A whitebackground ink was printed and dried on polyethylene bags. A 3 inch by 4inch rectangular region was printed using a standard transfer printingprocess. A printed graphic similar to that described above in theexample “Printed DISSOLVE-A-WAY® labels for plural time/temperature andtemperature monitoring devices” was printed in the center of a 6 inch by8 inch bag. The bag was used identically as that described in theexample “Printed DISSOLVE-A-WAY® labels for plural time/temperature andtemperature monitoring devices” (FIGS. 1A, 1B and 1C). The printedregion of the bag remained permanently attached to the bag.

Home-use water portable filter indicator for reporting time for filterchance: A label-based indicator was produced with a removable adhesivebacking for placement on a home use water filtration unit (Brita WaterFiltration Systems, Brita Products Company). The label had graphicsprinted to communicate and instruct the user when it was time to changethe water filter in the unit. The graphic had blue printed horizontalbar as a reference color and open bar with a white background runningparallel and adjacent to the blue printed horizontal bar. The open barwith white background was intended to be the area to be marked with theintrinsic expiration indicator.

Instructions were printed on the label indicating that when a pen filledwith the intrinsic expiration indicating material was used to mark theopen bar. A color would appear at the end of a 2 month period which wasequal in hue and intensity as the blue printed horizontal bar. When afilter was changed in the unit, the user marked the open bar area with apen containing a intrinsic expiration indicating material formulation.For the purpose of prolonged expiration (2 months at room temperature),a formulation was used containing a mixture of 150 mg/ml10,12-tricosadiynoic acid (GFS Chemical, Inc.) and 15 mg/ml10,12-pentacosadiynoic acid (GFS Chemical, Inc.) in a solvent systemconsisting of ethanol/chloroform (Aldrich Chemical, Inc.) 2/1volume/volume. This mixture and concentration of diacetylenic monomerswas selected based on its coloration over prolonged periods of time atroom temperature. The mixture was added to an empty felt tip pen forapplication to the descriptive label.

Pre-colored/polymerized plural intrinsic expiration indicator zone formark through inactive plural intrinsic expiration indicator:Pre-colored/polymerized plural intrinsic expiration indicating materialswere made by pre-coating and pre-polymerizing the material in a selectedzone on a label. An ink solution described above in the example “Solventbased ink formulation” was printed on a substrate to serve as thereference background for marking with a solvent soluble monomericintrinsic indicator. The zone was pre-polymerized with a hand heldultraviolet lamp (254 nanometer) and calibrated in coloration intensityto a hue which represented the coloration that the plural intrinsicexpiration indicating material would naturally turn to in a refrigeratorafter 3 days of storage (UV exposure for approximately 3 seconds at 12inches). The zone was printed on a label with graphics and instructionsfor use.

For use, the label was attached to a pre-portion bag filled with raw redmeat for storage. The color intensity of the pre-polymerized zone wasadjusted in intensity such that, when marked with a strike through markof the plural intrinsic expiration indicating material using a felt tippen, the marked area would turn color to match the background color ofthe pre-polymerized zone background. The mark was made with a felt tippen described above in the example “Monomer felt tip ink penapplicator”. Upon marking, the marked area caused the underlyingpre-polymerized zone to turn orange due to the solvent triggering fromthe felt tip pen ink solvent.

The label was applied to a storage bag. The bag was made with apolyester/polypropylene laminate and was heat sealed containing a meatmarinade. The label was marked for expiration on day 3 as previouslydescribed. The bag, containing an uncooked red meat marinade, was storedin a refrigerator and monitored twice per day each day after the labelwas marked. At day 2, the bag was removed and checked for perishability.The mark remained orange/purple and had not yet turned blue.Perishability was calibrated to be judged to occur when the orange markturned the same blue color as the background pre-polymerized zone. Atday 3 from marking and initial storage, the mark appeared to have thesame background color as the pre-polymerized zone and, therefore,indicated that the perishable meat contents should be used that day ordisposed.

Further, the mark was calibrated along with the pre-polymerizedbackground color that if the mark turned a darker blue than thepre-polymerized background color, then the contents of the bag hadexpired and should be disposed of rather than cooked and eaten.

This format has the advantage that the solvent in the application devicecan immediately trigger a color change in the pre-colored/polymerizedbackground indicating that the application device is charged with thesolvent solution and is not dried out. In addition, the solvent/monomersolution delivered to the substrate surface could be easily located onthe background by triggered mark. As the time/temperature processensues, the expiration indication can be visualized by a color change inthe mark. The mark will change color over time and depending ontemperature to become the same color as the backgroundpre-colored/polymer. The background color could be calibrated and usedas a reference color for indicating what the final color of theindicator should be in order to indicate when an attached item isperished.

Plural device with solvent saturated inactivation strip enclosureactivated by removing seal: An alternative activation means was createdby saturating a paper strip with the monomer ink formulation describedabove (see example: “Solvent based ink formulation”) and then sealingthe paper strip in a polyester plastic barrier. The monomer remainedinactive in the solvated state and until the plastic barrier wasremoved. Removal of the barrier permitted the solvent to evaporatethereby depositing dried plural intrinsic expiration initiation materialon the paper surface. The deposition of solid material initiated theprocess of coloration.

A strip of standard white filter paper (Whatman no. 2) was cut to a 0.5inch by 1 inch in dimension. The paper strip was placed and centered ona heat sealable polyester strip 0.75 inch by 2 inch in dimension. Thestrip was saturated with several drops of monomer ink formulation(above). A second heat sealable polyester strip with the same dimensionsas the first polyester strip was placed over the paper strip andlaminated to the lower polyester strip using mild heat sealing. Thesolvent saturated paper was hermetically sealed during the process. Themonomer ink formulation remained saturated after the sealing process.

A light blue reference decal (0.24 inch in diameter) was adhered to theend of one side of the outer part of the polyester enclosure such thatnone of the paper strip was obscured. The reference decal was calibratedin hue as to what the final color of the plural intrinsic expirationinitiation material coloration would be after 3 days exposure in arefrigerator.

The polyester enclosure was designed in a way that permitted the easypeeling of the upper strip from the lower strip while maintaining thepresence of the blue tinted reference color decal. The strip could beactivated by peeling off the upper polyester strip while keeping therest of the device intact.

The strip was adhered to a plastic bag containing a red meat andmarinade. The bag, contents and indicating strip were placed in arefrigerator (35-40° F.). After adherence using double stick tape, thestrip was activated by peeling off the upper polyester strip. Thesolvent evaporated and the time/temperature monitoring process wasinitiated. The strip coloration was monitored over several days. Thestrip turned to an identical light blue color after 3 days in therefrigerator indicating that the meat should be cooked on that day sinceit was the same color as the blue tinted reference decal.

It was further determined that the strip could be used to monitorcooking progression as described above (see example: Plurality devicefor time/temperature and 160° F. irreversible color change indicatingsubsequent cooking completion). The blue coloration of the strip couldbe used to monitor cooking completion in a microwave oven since theplural, intrinsic expiration indicator turned an orange colorirreversibly above 160° F.

Plural intrinsic expiration initiation device on pre-printed poroussubstrate to control coloration degree: DISSOLVE-A-WAY® labels, wereprinted similar to the example above (“Printed DISSOLVE-A-WAY® labelsfor plural time/temperature and temperature monitoring devices”).Solvent impermeable flexographic inks were used in the printing process.The color and hue were matched to a light blue (pantone color match). Ascreen pattern of dots (0.01 millimeter dia.) were printed from apercent coverage of 2%, 4%, 8%, 16%, 32% and 74% total area from thelowest percent on the left to the highest percent on the right. The dotpatterns were printed in circles 1.0 cm in diameter with a dark blue 1millimeter diameter ring as a border around each circle. The circleswere printed side-by-side 1.3 cm center-to-center. An additional clearcircle was printed to the left of the printed circles such that therewere a total of 7 circles lined up side-by-side. The circles were markedabove to indicate day 1 through day 7 of expiration.

The labels were used in an application similar to that described above(“Printed DISSOLVE-A-WAY® labels for plural time/temperature andtemperature monitoring devices”). The circle representing day 3 ofexpiration was marked with the monomer felt tip ink pen applicatorcontaining the plural intrinsic initiation expiration indicatingmaterial described above (“Plural intrinsic expiration indicator felttip pen applicator”).

As is evident by the description above and various examples, the subjectinvention provides for numerous advantages. The plurality of colorchanges provide for a continuum of perishable handling and processingmeans which can be simultaneously or sequentially monitored. Themonitoring process is simplified by the visual appearance of discretecolor changes that the indicating material undergoes during colorchanging traditions. Devices are activated at the point of usage ratherthan requiring cold storage or other inconvenient storage means toinhibit the initiation process. Devices can be made with simple low costsubstrate and the plural intrinsic material can be deposited on to asubstrate using a convenient low cost application means such as markingwith a felt tip pen.

Various geometries and configurations can be incorporated since thesubstrates can be made using conventional papers, labels and printingprocesses. Thus, processes for production can utilize existing highspeed printing process for mass production at low costs. Monomericdiacetylenic compounds can be readily adjusted in structure toaccommodate particular applications. Temperature and time frame forcolor development and plurality application can be assessed to designand synthesize a particular diacetylenic monomer with the attributes fora given application. Diacetylenic chemistries provide for the indicatingmaterial to be made reversible or irreversible depending on theapplication. Finally, the devices and indicators have broad applicationacross various perishable and time indicating applications.

Plural Polymeric Time-Temperature Substrates

The plural intrinsic time-temperature indicating system can be utilizedsuch that the time-temperature indicating material is pre-polymerized inone colored state and caused to change color to a second state by anactivating agent that interacts with the polymer polydiacetylene toinduce the color change. A solublized form of the diacetylenic monomercan be coated on to the surface of a substrate and polymerized to apolydiacetylene polymer. The polydiacetylene polymer can respond to anactivating agent by contacting the activating agent to the surface of apolydiacetylene layer. The activating agent can cause thepolydiacetylene layer to change color from a deep blue color to a brightred hue. The degree and rate of color change is time temperaturedependent. Time-temperature indicators are conveniently prepared byutilizing coated substrates with a polymerized polydiacetylenic layerand subsequently contacting the layer with an appropriate activating ortriggering agent that cause the layer to change from one color toanother. Low reaction temperatures (30-60° F.) are prolonged and highreaction temperatures (60-90° F.) are accelerated. Pluraltime-temperature/temperature or other formats are made possible byutilizing adjacent areas of the polydiacetylene-coated substrate as atemperature indicator or to other indication means.

Formats

A variety of formats can be used for revealing relevant messages tousers of the plural intrinsic time-temperature indicating system.Messages can be under or over-printed using a stationary ink that isobscured by the time-temperature indicating ink. The message can berevealed upon time-temperature indication and a color change in thetime-temperature material relative to the stationary ink. Messages canbe printed in the exact hue and color of the time-temperature ink andsurrounded by the time-temperature ink such that the color and contrastof each ink type gives the visual appearance of no message until themessage is revealed. Messages can be selectively generated on a printedtime-temperature substrate by first creating a patterned or printedmessage in a time-temperature activating material that comes in contactwith the initially colorized time-temperature substrate. When theprinted or patterned activating element is contacted with thetime-temperature indicating material, only the printed message will behighlighted to change color and give the appearance of revealing amessage.

Time-temperature triggering can be accomplished by introducing an activetriggering agent into the substrate in a dried form. The activetriggering agent is released from the substrate and allowed to interactwith the polydiacetylene layer in a time-temperature format when asolublizing agent is applied to the substrate. Upon application of thesolublizing agent, the active triggering agent is mobilized.

The substrate can have a printed immobilized triggering agent on itssurface or embedded and contiguous with the substrate surface. The agentwould be selected such that it would not have any initial color. Theagent could be printed in a useful message form. The time-temperaturematerial can be subsequently over printed over the latent printedtriggering agent. The triggering agent in its latent form is able toinitiate a color change in the time-temperature material since it is notmobile and can not diffuse without the addition of a diffusionstimulating or solublizing agent. The time-temperature process can beinitiated by applying a solublizing agent to the substrate surfacedirectly over the time-temperature material and over the region wherethe triggering agent has been printed and immobilized. When thesolublizing agent has saturated the substrate surface, the triggeringagent is mobilized, made free to diffuse and can interact with thetime-temperature material so as to initiate a color change in thetime-temperature material. Both diffusion and stimulation of a colorchange in the time-temperature material are both diffusion dependent andcan be made to work cooperatively to prolong or reduce thetime-temperature effect.

Solublizing agents can include water, polyethylene glycol, glycerol,inert oils that themselves do not cause a triggering effect inpolydiacetylene, inert silicon oils, inert non-volatile solvents (e.g.dimethylformamide), hydrating gels, and the like. The solublizing agentswill typically be present at 100% concentrations, but can be present inmixtures and at concentrations that are required for a particularapplication.

Various bar code elements or lines can be made to be more or lesstime-temperature responsive. One or more bar code lines or portions oflines can be printed with the time-temperature material such that aninitial scan, prior to a time-temperature event, can be used as acalibration event. As the time-temperature process is triggered with anactivating agent, certain elements of a bar code begin to change. Asubsequent scan can be used to monitor the progression of thetime-temperature process and quantitatively report the status of thefood type being monitored. The bar code can also possess a temperatureonly dependent element that will change color when a specifictemperature such as a cooking temperature is achieved, therefore,providing for a time-temperature/temperature plural intrinsic indicator.

Laminated contact configurations can be utilized for accurate deliveryand metering of the activating agent placed in contact with thetime-temperature coated substrate. Laminated contact configurationsinvolve coating an activating agent on one substrate element and coatingthe time-temperature indicating polydiacetylene polymer on a secondsubstrate. Initiation of the time-temperature process requires that thetwo substrates are laminated together such that the activating agent isplaced in direct proximal contact with the polydiacetylene layer. Thecontact between layers can be maintained during the time-temperatureindicating process.

Various laminating contact configurations are possible. Thetime-temperature polydiacetylene layer can be adhered to a transparentflexible substrate and be applied to an affixed opaque substratecontaining the activating agent. Alternatively, the activating agent canbe adhered to a transparent flexible substrate and applied to an affixedopaque substrate containing the time-temperature sensitivepolydiacetylene layer. Each configuration ban lead to the same result;however, production and packaging of the product formats will varydepending on the product configuration of choice.

Laminating substrates used for delivering either the time-temperatureindicating polydiacetylene or the time-temperature activating agent canbe made flexible or rigid. The substrate can be patterned with thematerial to be delivered or can be simple and non-patterned. Thematerial can be flood coated or applied in a % dot pattern. The materialcan be printed into a message form for revealing a message or deliver asimple mark circle, or icon. The material can be in a viscous gel fromor in a more permanent adhesive form such as the adhesive on a tape.Adhesives on a tape can be impregnated or formulated with the materialof interest such that the laminating process involves simply attaching atape piece to the apposing substrate for initiating the process.

The laminating substrate can be made of any of a variety of materialsincluding transparent plastic, tape, thin almost transparentDissolve-A-Way® label stock, water soluble materials such as those usedin breath strips, nitrocellulose-based materials, wax papers,cellophane, vinyl, polyvinyl acetate, polypropylene, polyethylene,acrylic, polystyrene, any of a variety of suitable plastic compositions,glass, foils, films, acetate transparency materials, adhesivesubstrates, elastic compositions, food grade materials or the like.

Substrates

A wide range of substrate types can find use for producing pluralintrinsic time-temperature indicators. Paper, plastic, plastic sheet,Tyvek™ sheet, fiber, glass, metal, composite materials, fibrousmaterials, compounded materials, coated materials, painted surfaces,Dissolve-A-Way® materials, printed surfaces and the like can be used.The substrate can be a pressure sensitive label, be adhesive ornon-adhesive, can be thick or thin, can be flexible or rigid, can belaminated or unlaminated, can be clear or opaque, can be smooth orrough, or can be coated or uncoated. Coated substrate areas can becontinuous or discontinuous. Discontinuous substrate coatings orvariable substrate coatings can find use as a means to regulate thesensitivity of a time-temperature indicator. The substrate surfaceshould be compatible with food or substances intended to be monitored.The substrate can be a part of a container of food, attached to acontainer of food, or used along with a container of food.

Substrates can come in various thicknesses depending on the intendedapplication of interest. Substrates can range from 0.1/1000 to 250/1000of an inch thick. More often, substrates will range from 1/000 to100/1000 of an inch thick. Usually, selected substrates will range from2/1000 to 20/1000 of an inch thick. The thickness will more often dependon the product format rather than the functionality of thetime-temperature indicating process. The substrate flexibility will beimportant particularly when it will be applied to a surface intended tobe monitored for the purpose of monitoring a time temperature process.

Indicating Compositions

Monomer type diacetylenic monomers can be selected based on theirreactivity for a particular use as a time-temperature indicator orplural intrinsic indicator. Medium to long chain diactylenic fatty acidsfind use to comprise time-temperature indicators. The diacetyleniccompound can be shorter in length for increased reactivity (14 carbonatoms in length) or longer in length for reduced activity (25 atoms inlength or more). Typically carboxylated head groups such as a carboxylicacid can be utilized to facilitate an irreversible and permanent colorchange during a time-temperature indication process. Representativecompounds include 10,12-tricosadiynoic acid (23 carbon atoms in length)and 10,12-pentacosadiynoic acid (25 carbon atoms in length).

The diacetylenic group can be positioned closer or more distil to thelipid's polar head group. The diacetylene moiety can be 2 to 18 carbonsaway from the polar head group in the 2, 4; 3, 5; 4, 6; 5, 7; 6, 8; 7,9; 8, 10; 9, 11; 10, 12; 13, 15; 14, 16; 15, 17; or 18, 20 positions.More often the diacetylene moiety will be in the 3, 5 to 14, 16 positionand most often, the diacetylene moiety will be in the 5, 7 to 10, 12position. The exact position will depend on the application of interestand synthesis procedures required for making the compound of interest.

Coating compositions comprising the diacetylenic monomer areconveniently prepared by dissolving the monomeric diacetylene materialin an organic solvent or solvent-based ink. Typical organic solventsincluding ethanol, propanol, acetone, chloroform, dichloromethane, ethylacetate, diacetone solvents, diethyl ether, hexane, benzene, and thelike can be used accordingly to dissolve the diacetylenic monomer.Concentrations for coating compositions can range from 500 mg/ml to 1.0mg/ml. More usually, concentrations will range from 250 mg/ml to 10mg/ml. Typically, concentrations will range from 150 mg/ml to 50 mg/ml.

The coating composition can be comprised purely of an evaporatingsolvent and the diacetylenic monomer or can include a resin or matrixthat becomes co-dried along with the monomer. The resin or matrix caninclude materials that act as binders to enhance the binding of thediacetylenic material to the substrate. Resins or matrix components caninclude nitrocellulose, adhesives, plastics, gums, waxes, pigments, orthe like which do not interfere with the diacetylenic material's abilityto polymerize and act as a time-temperature indicator.

The coating composition can be ink jet printed, sprayed, painted,layered, dip coated, nebulized, dropped, applied with an applicator,applied with a pen or felt tip, applied by blotting, printedflexographically, printed by off-set printing, printed digitally,printed using methods such as Indigo™ printing, Gravier printing, andthe like. The printing process utilized must be capable of delivering auniform coating of the diacetylene monomer such that the monomer can beevenly distributed into a microcrystalline layer on the surface of thesubstrate.

Substrates comprising an evenly distributed microcrystalline layer ofdiacetylenic monomeric material can be exposed to ultraviolet light (254nanometers). The monomeric diacetylenic crystals turn from a colorlessto blue color upon exposure to ultraviolet light. The blue colorintensity can be adjusted from very light blue colors to deep darkblue/black hues. A time-temperature polydiacetylene coated substrate canbe adjusted to be more or less to a time-temperature sensitive toactivating agents depending on the level of ultraviolet light exposureand subsequent level of polymerization. Low levels of polymerizationresulting in light blue polydiacetylene coatings typically results inmore sensitive time-temperature substrates. High levels ofpolymerization resulting in dark blue polydiacetylene coatings typicallyresults in less sensitive time-temperature coatings.

Activating/Triggering Agents

Activating agents capable of inducing a time-temperature color changetransition in polydiacetylene include aggressive solvents, oils, balms,acids, bases, flavors and aromas in an oil/liquid form, lubricants,menthol based compositions, polymer based oils, essential oils and avariety harsh organic or inorganic compositions that can disrupt theoriented blue form of polydiacetylenic crystals thereby inducing a colorchange from the blue form of the polymer to a red form of the polymer.

Activators include various cooking oils, balms, natural oils such clove,peppermint, and spearmint, greases, butter, saturated and unsaturatedfats, and a variety of other fat or solvent based materials which whenin contact with the blue form of a polydiacetylenic material convertedthe polydiacetylene to the red form. Activators were further selectedbased on their ability to trigger the temperature transition rapidly atroom temperature from 1 to 4 hours and slowly at chilled temperaturesfrom 2 to 4 days.

It is important that the activating/triggering agent remains localized,adhered to, and concentrated on a printed polydiacetylenic substrateduring the duration of a time-temperature indicating period. Placement,uniformity of application, physical state, and adequate agent diffusionall play a role in maintaining the adequacy of the triggering effectduring the indication process.

Activating/triggering agents can be used in a pure form or added inconcentrations to an inert carrier composition that itself does notimpart any triggering characteristics. The activating agent can bepresent from 0.001% to 100%. Usually, the activating agent will bepresent from 0.01% to 90% in an inert carrier matrix. More usually, theactivating agent will be present from 0.1% to 50% in an inert carriermatrix. Typically, the activating agent will be utilized from 0.1% to10% in an inert carrier matrix.

The inert carrier matrix is selected based on its characteristics formobilizing and transporting the activating/triggering agent to interactwith the time-temperature indicating polydiacetylene material coated ona substrate. It is desirable that the activating/triggering agent issolublized and evenly distributed in the matrix of the inert carriercomposition. Likewise, it is desirable that the inert carrier matrix hasthe property of low volatility to ensure that it does not evaporateduring the time-temperature indicating process. The inert carrier matrixshould facilitate good diffusion of the activating/triggering agent. Theinert carrier matrix should remain in a fluid form without crystallizingduring low-temperature time-temperature indication. The inert carriermatrix should maintain good solublization of the activating/triggeringagent through out various temperature ranges that the time-temperaturesystem is to be utilized.

The inert carrier matrix can be formulated with inactive oils,polyethylene glycols, polypropylene glycols, glycerol, low viscositypolyvinyl acetates, adhesive compositions, Interlemer™ compositions, lowmelting waxes, inert silicon oils, inert hydrocarbon oils, low viscosityand diffusing materials such as silicon rubbers, gels, gelatins, gumsand the like. The inert carrier matrix selected will, depending on thephysical, chemical, and commercial considerations, be involved in thefinal product.

Referring to FIGS. 4A, 4B, 4C and 4D, there is shown a time-temperatureand temperature monitoring marking device in the form of label 120. Thelabel 120 has printed thereon a diacetylenic monomer which waspolymerized to a polydiacetylene polymer as discussed in Example 1below. Thereafter, a transparent activating agent, for example, a mintlip balm such as one manufactured by Blistex Corporation, was applied inthe shape of an X as designed by the numeral 121. As shown in FIG. 4B,the mark X 121 is shown in dashed lines as it was transparent and notreadily visible. The balm serves as the time-temperature activatingagent. After a specified length of time at a specified temperature, theX mark 121 causes the activated polydiacetylene polymer underlying themark X 121 to turn from a dark blue color to a bright red/orange in atwo to four day time period at 45° F. or in two to four hours at roomtemperature. The remaining surface portion of the label 120′outside ofthe X-mark 121′ area remains the dark blue color as shown in FIG. 4C. Atsuch time as the label is brought to a high threshold temperature, forexample 140° F., the portion of the label outside of the X-mark 121 willchange to a bright orange as shown in FIG. 4D.

Examples 1, 2 and 3 provide further details of the specific labels andtests related to the embodiment of FIGS. 4A, 4B, 4C and 4D.

EXAMPLES Example 1

Preparing ink jet printed time-temperature/temperature pressuresensitive Dissolve-A-Way® label substrates: Dissolve-A-Way® label(DayMark Corporation) was ink jet printed using a solution of 150 mg/ml10,12-tricosadiynoic acid dissolved in chloroform/ethanol 1/1 v/v.Dissolve-A-Way® sheets were cut to 8.5 inch by 11 inch and inserted intoan ink jet printer (HP PSC 2210). The print setting was configured forphoto-quality to ensure the highest ink delivery. The black ink jetcartridge was utilized for delivering the time-temperature inkcomposition. An empty cartridge was opened by removing the top plate,thoroughly cleaned with water and then rinsed and dried with ethanol.The cartridge was filled with 10 ml aliquots of solution (above),re-inserted in the printer and printing initiated. Solid print areaswere designated that completely covered the page with the exception of aslim border. Printed sheets were activated by polymerization withultraviolet light (254 nm). A 6 bulb (18 inch low pressure mercuryvapor) light bank was used for polymerization. The distance between thesheet and printed substrate was maintained at 18 inches. The degree ofpolymerization was established by controlling the total exposure time.Upon polymerization, the white printed sheets turned intensely blue.

A mint lip balm (Blistex Corporation) was used as the time-temperatureactivating agent. Balm marks were applied in generous marks at roomtemperature. Half of the marked Dissolve-A-Way®pieces were left at roomtemperature and the other half were placed in a refrigerator at 45° F.

The marked Dissolve-A-Way®pieces kept at room temperature transitionedfrom a deep blue color to a bright orange color within a 4 hour period.Each of 4 marks were consistent in the time and degree of color change.The marked pieces kept at 45° F. transitioned from a deep blue color toan orange color by the end of 4 days. Each of 4 marks exhibitedconsistency in color change over the time period.

The blue printed areas surrounding the marked areas on the chilledsubstrates remained temperature active. The surrounding areas thatremained blue exhibited a strong plural intrinsic thermochromic effect.As a piece of the printed Dissolve-A-Way® substrate was attached to amicrowavable piece of meat sealed in a plastic tub and heated, thesurrounding blue area transitioned to a bright orange to match the colorchange of the area that had been triggered to change color during thetime-temperature indication period. The temperature dependent colorchange of the surrounding blue area occurred irreversibly at 160° F.Subsequently, the Dissolve-A-Way® time-temperature pieces were easilyand readily removed from the plastic tub by contact with water. Thelabel and its composition immediately dissolved into the water.

Example 2

Preparing ink jet printed time-temperature/temperature Tyvek™substrates: The plastic film Tyvek™ (Du Pont Company) was ink jetprinted using a solution of 150 mg/ml 10,12-tricosadiynoic aciddissolved in chloroform/ethanol 1/1 v/v. Tyvek™ sheets were cut to 8.5inch by 11 inch and inserted into an ink jet printer (HP PSC 2210). Theprint setting was configured for photo-quality to ensure the highest inkdelivery. The black ink jet cartridge was utilized for delivering thetime-temperature ink composition. An empty cartridge was opened byremoving the top plate, thoroughly cleaned with water and then rinsedand dried with ethanol. The cartridge was filled with 10 ml aliquots ofsolution (above), re-inserted in the printer and printing initiated.Solid print areas were designated that completely covered the page withthe exception of a slim border. Printed sheets were activated bypolymerization with ultraviolet light (254 nm). A 6 bulb (18 inch lowpressure mercury vapor) light bank was used for polymerization. Thedistance between the sheet and printed substrate was maintained at 18inch. The degree of polymerization was established by controlling thetotal exposure time. Upon polymerization, the white printed sheetsturned intensely blue.

A mint lip balm (Blistex Corporation) was used as the time-temperatureactivating agent. Balm marks were applied in a generous marks at roomtemperature. Half of the marked Tyvek™ pieces were left at roomtemperature and the other half were placed in a refrigerator at 45° F.

The marked Tyvek™ pieces kept at room temperature transitioned from adeep blue color to a bright orange color within a 4 hour period. Each of4 marks were consistent in the time and degree of color change. Themarked pieces kept at 45° F. transitioned from a deep blue color to anorange color by the end of 4 days. Each of 4 marks exhibited consistencyin color change over the time period.

The blue printed areas surrounding the marked areas on the chilledsubstrates remained temperature active. The surrounding areas thatremained blue exhibited a strong plural intrinsic thermochromic effect.As a piece of the printed Tyvek™ substrate was attached to amicrowavable piece of meat sealed in a plastic bag, the surrounding bluearea transitioned to a bright orange to match the color change of thearea that had been triggered to change color during the time-temperatureindication period. The temperature dependent color change of thesurrounding blue area occurred irreversibly at 160° F.

Example 3

Pre-printed plural intrinsic time-temperature indicator flexographicallyprinted on pressure sensitive label stock: A pre-polymerize/sensitizedlayer of polymeric polydiacetylene was formed using a nitrocellulose inkbase and printed using a flexographic printing process. The ink base wasmade using a common solvent-based nitrocellulose ink base used insolvent base flexographic printing process. The solvent carrier was usedto dissolve a mixture of 15% by weight 10, 12 tricosadiynoic acid and1.5% by weight 10, 12 pentacosadiynoic acids. The ink base was purchasedfrom Wykoff Corporation. The monomeric diacetylenic acids were added totheir corresponding concentrations, mixed and dissolved in the ink base.

After formulation of the ink base, the formulated ink was printed on toa pressure sensitive label stock using a flood coating technique toensure complete coverage on the printed substrate. The printed substratewas dried using an attached blow dryer in the printing unit. Afterprinting and drying, the formulated ink was sensitized to thepolydiacetylenic form by exposure to ultraviolet light (254 nm). Thepolymerization process converted the uncolored white substrate to a bluecolor indicating the formation of the polydiacetylenic form.

The polydiacetylenic pre-polymerized layer coated on the pressuresensitive label substrate was used in a time-temperature and temperatureindication trial. Time and temperature sensitive activators were used toconvert the blue form of the polydiacetylenic layer to a red form bydirectly contacting the polydiacetylenic layer with the activator.Activators were selected based on their ability to convert the bluepolydiacetylenic material to the orange form of the polydiactylenicmaterial. A mint lip balm (Blistex Corporation) was used as anactivating agent. Balm marks were applied in generous marks at roomtemperature. Half of the marked substrates were left at room temperatureand the other half were placed in a refrigerator at 45° F.

The marked substrates kept at room temperature transitioned from a deepblue color to a bright orange color within a 4 hour period. Each of 4marks were consistent in the time and degree of color change. The markedsubstrates kept at 45° F. transitioned from a deep blue color to anorange color by the end of 4 days. Each of 4 marks exhibited consistencyin color change over the time period.

The blue substrate areas surrounding the marked areas on the chilledsubstrates remained temperature active. The surrounding areas thatremained blue exhibited a strong plural intrinsic thermochromic effect.As a piece of the pressure sensitive label substrate was attached to amicrowavable piece of meat sealed in a plastic bag, the surrounding bluearea transitioned to a bright orange to match the color change of thearea that had been activated to change color during the time-temperatureindication period. The temperature dependent color change of thesurrounding blue area occurred irreversibly at 160° F.

Example 4

Preparing message revealing time-temperature/temperature indicator:Dissolve-A-Way® (DayMark Corporation) pressure sensitive substrate waspre-printed using an ink jet printing means with warning messages. Thewarning messages included but were not limited to: “Use Immediately”,“Discard”, “Expired”, “X-Pired”, “Do Not Consume”, “Reject”, and relatedwarning messages. The messages were printed with a light blue hue suchthat they could be obscured later with darker blue over-print of thetime-temperature material.

The Dissolve-A-Way® substrate was over printed using a solution of 150mg/ml 10,12-tricosadiynoic acid dissolved in chloroform/ethanol 1/1 v/v.Dissolve-A-Way® sheets were cut to 8.5 inch by 11 inch and inserted intoan ink jet printer (HP PSC 2210). The print setting was configured forphoto-quality to ensure the highest ink delivery. The black ink jetcartridge was utilized for delivering the time-temperature inkcomposition. An empty cartridge was opened by removing the top plate,thoroughly cleaned with water and then rinsed and dried with ethanol.The cartridge was filled with 10 ml aliquots of solution (above),re-inserted in the printer and printing initiated. Solid print areaswere designated that completely covered the page with the exception of aslim border. Printed sheets were activated by polymerization withultraviolet light (254 nm). A 6 bulb (18 inch low pressure mercuryvapor) light bank was used for polymerization. The distance between thesheet and printed substrate was maintained at 18 inch. The degree ofpolymerization was established by controlling the total exposure time.

Upon polymerization, the white printed regions and under-printed messageareas turned intensely blue. The blue coloration of thetime-temperature/temperature indicating polydiacetylene layer wasintense enough to obscure the under-printed message regions.Under-printed messages and over-printed time-temperature colorations andintensities could readily be adjusted to provide maximum obscurity priorto activation and maximum contrast after activation and revealing.

A mint lip balm (Blistex Corporation) was used as the time-temperatureactivating agent. Balm marks were applied in generous marks at roomtemperature directly over the message printed regions. Half of themarked Dissolve-A-Way® pieces were left at room temperature and theother half were placed in a refrigerator at 45° F.

The marked Dissolve-A-Way® pieces kept at room temperature transitionedfrom a deep blue color to a bright orange color within a 4 hour periodand revealed the underlying message. Each of 4 marks were consistent inthe time and degree of color change. The marked pieces kept at 45° F.transitioned from a deep blue color to an orange color by the end of 4days and revealed the under-printed message. Each of 4 marks exhibitedconsistency in color change over the time period.

The blue printed areas surrounding the marked areas on the chilledsubstrates remained temperature active. The surrounding areas thatremained blue exhibited a strong plural intrinsic thermochromic effect.As a piece of the printed Dissolve-A-Way® substrate was attached to amicrowavable piece of meat sealed in a plastic tub, the surrounding bluearea transitioned to a bright orange to match the color change of thearea that had been ‘triggered to ’ change color during thetime-temperature indication period. The temperature dependent colorchange of the surrounding blue area occurred irreversibly at 160° F.Subsequently, the Dissolve-A-Way® time-temperature pieces were easilyand readily removed from the plastic tub by contact with water. Thelabel and its composition immediately dissolved into the water.

Referring to FIGS. 5A, 5B, 5C and 5D, there is shown another embodimentof a time-temperature and temperature monitoring device generallydesignated by the numeral 130 having a plurality of layers adapted to belaminated together, namely, a first layer 132 and a second layer 134such as a transparent tape. The first layer 132 includes a printedpolymeric area 146 having a time-temperature and temperature sensitivecoating such as polydiacetylene on the surface facing the second layer134 and a border 147 around said printed polymeric area 146. The secondlayer 134 has one end 144 attached to one end of the first layer 132 toform a hinge. As can be seen in FIG. 5A, a first portion 148 of thelaminating surface of the second layer 134 has been contacted with theactivating agent such as a lip balm for example. The remaining portion149 of the laminating surface of the second layer 134 does not have anactivating agent thereon. If desired, such remaining portion 149 and/orthe border 147 may have adhesive for adhering the second layer 134 tothe first layer 132.

As shown in FIG. 5B, immediately after engagement of the laminatingsurface of the second layer 134 into interfacial relationship with thetime-temperature and temperature sensitive coating of the printedpolymeric area 146, said area 146 will remain its original color, bluefor example, and will leave a blue appearance throughout the surface ofthe transparent tape functioning as the second layer 134 including thatportion underlying both the first portion 148 coated with the activatingagent and the second portion 149, provided the activating agent iscolorless as applied.

FIG. 5C shows a distinct color change in the area 143 after a period oftwo to four days at 45° F. or two to four hours at room temperaturefollowing engagement of the second layer 134 to the first layer 132 andactivation of the polymeric coating in the printed polymeric area 146contacted by the activating agent on the first portion 148. That portionof the area 146 not underlying the activating agent namely, theremaining portion 149 remains its original color, for example, darkblue. Thereafter, when the monitoring device 130 is heated to aspecified temperature, for example 160° F., that portion of the printedpolymeric area underlying the remaining portion 149 of the second layer134 also turns to a bright red/orange matching the color of the areaunderlying the first portion 148 with the activating agent as shown inFIG. 5D.

Examples 5 and 6 set forth further details with respect to actualsamples produced relative to the laminated embodiment of FIGS. 5A, 5B,5C and 5D.

Example 5

Laminating time-temperature/temperature substrates: Tyvek™ (Du PontCompany) was ink jet printed using a solution of 150 mg/ml10,12-tricosadiynoic acid dissolved in chloroform/ethanol 1/1 v/v asabove. The substrate sheets were cut to 8.5 inch by 11 inch and insertedinto an ink jet printer (HP PSC 2210). The print setting was configuredfor photo-quality to ensure the highest ink delivery. The black ink jetcartridge was utilized for delivering the time-temperature inkcomposition. An empty cartridge was opened by removing the top plate,thoroughly, cleaned with water and then rinsed and dried with ethanol.The cartridge was filled with 10 ml aliquots of solution (above),re-inserted in the printer and printing initiated. Solid print areaswere designated that completely covered the page with the exception of aslim border. Printed sheets were activated by polymerization withultraviolet light (254 nm). A 6 bulb (18 inch low pressure mercuryvapor) light bank was used for polymerization. The distance between thesheet and printed substrate was maintained at 18 inch. The degree ofpolymerization was established by controlling the total exposure time.Upon polymerization the white printed sheets turned intensely blue.

A mint lip balm (Blistex Corporation) was used as the time temperatureactivating agent. Saturating amounts of the balm were applied to onehalf of a transparent tape piece (0.5 inch wide and 2 inch long). A0.125 inch piece of tape was left uncoated at the end so as to providefor an adhesive area on both sides of the balm coated area. The tape wasadhered to the time-temperature substrate such that the balm initiallydid not contact the substrate. Eight individual pieces with balm affixedtape strips were prepared. Half of the pieces were left at roomtemperature and the other half were placed in a refrigerator at 45° F.The time-temperature process was initiated by sealing the balm affixedareas to the time-temperature substrate and making complete and sealedcontact with the balm to the substrate.

The pieces kept at room temperature transitioned from a deep blue colorto a bright orange color within a 4 hour period. Each of 4 affixed balmareas were consistent in the time and degree of color change. The markedpieces kept at 45° F. transitioned from a deep blue color to an orangecolor by the end of 4 days only on the balm contact regions. Each of 4balm affixed regions exhibited consistency in color change over the timeperiod.

The blue printed areas surrounding the balm/tape contact areas on thechilled substrates remained temperature active. The surrounding areasthat remained blue exhibited a strong plural intrinsic thermochromiceffect. As a piece of the printed Tyvek™ substrate was attached to amicrowavable piece of meat sealed in a plastic bag, the surrounding bluearea transitioned to a bright orange to match the color change of thebalm contact area that had been triggered to change color during thetime-temperature indication period. The temperature dependent colorchange of the surrounding blue area occurred irreversibly at 160° F.

The process was repeated using a variety of different printedtime-temperature substrates, time-temperature activating agents,transparent tape adhesive materials, and geometries for initiating thecontact between the time-temperature system components. Bothnon-dissolving label material and label material of the type used forDissolve-A-Way® labels were employed.

Example 6

Laminating dissolvable time-temperature/temperature substrates:Dissolve-A-Way® (DayMark Corporation) label was, ink jet printed using asolution of 150 mg/ml 10,12-tricosadiynoic acid dissolved inchloroform/ethanol 1/1 v/v as above. The substrate sheets were cut to8.5 inch by 11 inch and inserted into an ink jet printer. (HP PSC 2210).The print setting was configured for photo-quality to ensure the highestink delivery. The black ink jet cartridge was utilized for deliveringthe time-temperature ink composition. An empty cartridge was opened byremoving the top plate, thoroughly cleaned with water and then rinsedand dried with ethanol. The cartridge was filled with 10 ml aliquots ofsolution (above), re-inserted in the printer and printing initiated.Solid print areas were designated that completely covered the page withthe exception of a slim border. Printed sheets were activated bypolymerization with ultraviolet light (254 nm). A 6 bulb (18 inch lowpressure mercury vapor) light bank was used for polymerization. Thedistance between the sheet and printed substrate was maintained at 18inch. The degree of polymerization was established by controlling thetotal exposure time. Upon polymerization, the white printed sheetsturned intensely blue.

A mint lip balm (Blistex Corporation) was used as the time-temperatureactivating agent. Saturating amounts of the balm were applied to onehalf of a thin transparent piece of Dissolve-A-Way® (DayMarkCorporation) label material (0.5 inch wide and 2 inch long). A sectionof Dissolve-A-Way® was left uncoated at the end so as to provide for anadhesive area on both sides of the balm coated area. TheDissolve-A-Way®label material was adhered to the time-temperaturesubstrate such that the balm initially did not contact the substrate.Eight individual pieces with balm affixed were prepared. Half of thepieces were left at room temperature and the other half were placed in arefrigerator at 45° F. The time-temperature process was initiated bysealing the balm affixed areas to the time-temperature substrate andmaking complete and sealed contact with the balm to the substrate.

The pieces kept at room temperature transitioned from a deep blue colorto a bright orange color within a 4 hour period. Each of 4 affixed balmareas were consistent in the time and degree of color change. The markedpieces kept at 45° F. transitioned from a deep blue color to an orangecolor by the end of 4 days only on the balm contact regions. Each of 4balm affixed regions exhibited consistency in color change over the timeperiod.

The blue printed areas surrounding the balm contact areas on the chilledsubstrates remained temperature active. The surrounding areas thatremained blue exhibited a strong plural intrinsic thermochromic effect.As a piece of the printed Dissolve-A-Way® label material substrate wasattached to a microwavable piece of meat sealed in a plastic bag andheated, the surrounding blue area transitioned to a bright orange tomatch the color change of the balm contact area that had been triggeredto change color during the time-temperature indication period. Thetemperature dependent color change of the surrounding area from blue toorange occurred irreversibly at 160° F.

Referring to FIGS. 6A, 6B, 6C and 6D, there is shown a furtherembodiment of a time-temperature and temperature monitoring devicegenerally designated by the numeral 170 incorporating a bar code feature160. The device 170 includes a substrate 171 having a surface on whichbars of the bar code 160 are printed. With reference to FIG. 6A, allbars of the bar code 160 except those designated by the numerals 162,163 and 164 ate printed with a stationary fixed dark blue or black printcolor such as ink that is not susceptible to color change. Those barsdesignated by the numerals 162, 163 and 164 are printed with atime-temperature sensitive polymer, namely, polydiacetylene, which has adark blue or black color that matches the remaining bars in the bar code160. The bar code 160, including bars 162, 163 and 164, comprises afully readable bar code in the initial unactivated state of bars 162,163 and 164.

The device 170 has a border area 161 encircling the bar code 160.Polydiacetylene is also applied to the border area. As previouslydiscussed, the polydiacetylene may initially be applied as acetylenemonomer and then polymerized, for example, by subjecting it toultraviolet light.

FIG. 6B shows schematically the application of an activating agentthroughout zone 165 encircling the bar code 160 and, therefore appliedto all bars including bars 162, 163 and 164. The activating agent istransparent and fully covers the complete bar code 160. The activatingagent is not applied to the border area 161. Following initialapplication of the activating agent, there is no change in any of thebar members including those designated by the numerals 162, 163 and 164.However, following application of the activating agent, those bars 162,163 and 164 printed with the time-temperature sensitive polymer willchange from a dark blue/black color previously described with referenceto FIG. 6A to a bright red/orange color (see FIG. 6C) after two to fourdays at 45° F. or two to four hours at room temperature. The change incolor of the bars 162, 163 and 164 renders them unreadable by a bar codescanner with the overall result that the bar code 160 has beenreconstituted to a different configuration shown in FIG. 6C therebyproviding a different readable state for the bar code. The change causedby the time-temperature indication process is such that the modified barcode shown in FIG. 6C can itself act as an objective readable code toindicate food freshness for food to which the device 170 is affixed.

As shown in FIG. 6C, the border area 161 coated with the temperaturesensitive polymer polydiacetylene remains a dark blue. Thus, the border161 remains unaffected during the time-temperature process/transitionfrom the condition of FIG. 6B to the condition of FIG. 6C as such borderarea 161 has not been contacted by the activating agent which waslimited to zone 165. The border 161 remains dark blue/black at alltemperatures until the device is raised to a predetermined temperature,for example 140° F. or 160° F. at which time it changes from the darkblue/black color of FIGS. 6A, 6B and 6C to a bright red/orange color asshown in FIG. 6D indicating that the food stuff to which the device isattached has been raised to the specified temperature.

Example 7

Time-temperature/temperature indicating bar code: A bar code-basedsystem was developed such that the time-temperature and temperaturechange components of the plural indicating product could be readobjectively with a bar code reader. Tyvek™ (Du Pont Company) was ink jetprinted using a solution of 150 mg/ml 10, 12-tricosadiynoic aciddissolved in chloroform/ethanol 1/1 v/v as above. The substrate sheets'were cut to 8.5 inch by 11 inch and inserted into an ink jet printer (HPPSC 2210). The print setting was configured for photo-quality to ensurethe highest ink delivery. The black ink jet cartridge was utilized fordelivering the time-temperature ink composition. An empty cartridge wasopened by removing the top plate, thoroughly cleaned with water and thenrinsed and dried with ethanol. The cartridge was filled with 10 mlaliquots of solution (above), re-inserted in the printer and printinginitiated. Bar code elements were printed using standard configurationsfor UPC bar codes. Printed areas were activated by polymerization withultraviolet light (254 nm). A 6 bulb (18 inch low pressure mercuryvapor) light bank was used for polymerization. The distance between thesheet and printed substrate was maintained at 18 inch. The degree ofpolymerization was established by controlling the total exposure time.Upon polymerization, the white printed bar code areas turned intenselyblue.

UPC bar codes printed with the time-temperature material were scannedwith an appropriate bar code reader. So long as the bar code retainedits dark blue contrast against the white background, the bar coderemained readable. When the time-temperature material transitioned froma dark blue color to a bright red/orange color, the bar code becameunreadable and registered with the bar code reader as a differentialresult. The differential result was interpreted as a threshold time foradequate change in the time-temperature material to indicate that foodheld at that temperature and time should no longer be consumed.

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically indicatedto be incorporated by reference.

The invention now being fully described, it will be apparent to one ofordinary skill in the art that many changes and modifications can bemade thereto without departing from the spirit or scope of the appendedclaims.

1. A method for monitoring plural functions of goods comprising thesteps of: (a) providing a substrate; (b) applying diacetylene monomer tosaid substrate; (c) polymerizing said monomer to form a coating ofpolydiacetylene, said coating having properties of (1) changing from afirst color irreversibly to a second color immediately upon beingsubjected to a specified temperature and (2), upon activation uponcontact by an activating agent, changing from said first color to saidsecond color at a temperature lower than said specified temperatureafter a time delay of at least one hour; (d) providing a second layerhaving at least a first discrete area and a second discrete area; (e)applying said activating agent to said first discrete area but not tosaid second discrete area; (f) affixing said second layer to saidsubstrate with the activating agent of said first discrete area engagingsaid coating; (g) maintaining or bringing said affixed coated substrateto a temperature below said specified temperature to cause that portionof the substrate contacted by said first discrete area to change to saidsecond color; and (h) thereafter heating said coated substrate to saidspecified temperature to cause that portion of the substrate contactedby said second discrete area to change to said second color.
 2. Themethod according to claim 1 further including the step of affixing saidcoated substrate to goods or to a container holding said goods.
 3. Themethod according to claim 1 wherein said substrate has printed thereon auniversal bar code comprising a number of discrete bars, some of saidbars lying in said first discrete area and other of said bars lyinginside said second discrete area.
 4. The method according to claim 1,further including the step of subjecting said diacetylene monomer toultraviolet light to thereby cause it to polymerize.
 5. The methodaccording to claim 1 wherein said activating agent is a member of thegroup consisting of oils, menthol, organic and inorganic acids andbases, balm compositions and organic flavors and aromatics.
 6. A methodfor monitoring expiration of goods comprising (a) providing a substratehaving a surface with first and second discrete areas; (b) applying abar code to said surface, said bar code comprising a series of discretemarks, said discrete marks formed using diacetylene monomer some but notall of said discrete marks lying within said first discrete area; (c)directing ultraviolet light to said surface to polymerize saiddiacetylene monomer to form polydiacetylene, said polydiacetylene havingthe property of (1) changing from a first color irreversibly to a secondcolor immediately upon being subjected to a specified temperature and(2), upon activation contact by an activating agent, changing from saidfirst color to said second color at a temperature lower than saidspecified temperature after a time delay of at least one hour; (d)applying said activating agent to said discrete marks in said firstdiscrete area but not in said second discrete area; (e) affixing saidsubstrate to goods or to a container containing said goods; and, (f)heating said goods to cooking temperature above said specifiedtemperature.
 7. The method according to claim 6 wherein said activatingagent is a member of the group of oils, methol, organic and inorganicacids and bases, balm compositions and organic flavors and aromatics. 8.A method for monitoring plural functions of goods comprising the stepsof: (a) providing a substrate; (b) applying to said substrate auniversal bar code comprising a number of discrete bars, some of saidbars being printed with a polydiacetylene coating, said coating havingproperties of (1) changing from a first color irreversibly to a secondcolor immediately upon being subjected to a specified temperature and(2), upon activation upon contact by an activating agent, changing fromsaid first color to said second color at a temperature lower than saidspecified temperature after a time delay of at least one hour; (c)applying said coating to said substrate in an area spaced from saiddiscrete bars printed with said coating; (d) applying said activatingagent to some but not all of said bars printed with said coating; (e)affixing said substrate with said coating to said goods or to acontainer containing such goods; (f) maintaining or bringing saidaffixed substrate to a temperature lower than said specifiedtemperature; and (g) thereafter heating said substrate to said specifiedtemperature.
 9. The method according to claim 8 further including thestep of maintaining said affixed substrate below said specifiedtemperature for such period of time as to cause the bars printed withsaid coating and contacted by said activating agent to change to saidsecond color.
 10. The method according to claim 8 wherein saidactivating agent is applied to said bars printed with said coating afteraffixing said substrate to said goods or said container.
 11. The methodaccording to claim 8 wherein said coating is applied by first applying adiacetylenic monomer and thereafter polymerizing it to a polydiacetylenepolymer.
 12. The method according to claim 11, further including thestep of subjecting said diacetyenic monomer to ultraviolet light tothereby cause it to polymerize.
 13. A device for monitoring pluralfunctions of goods comprising: (a) a substrate; (b) a polydiacetylenecoating on first and second discrete areas of said substrate, saidcoating having properties of (1) changing from a first colorirreversibly to a second color immediately upon being subjected to aspecified temperature and (2), upon activation upon contact by anactivating agent, changing from said first color to said second color ata temperature lower than said specified temperature after a time delayof at least one hour; and (c) an activating agent applied to saidcoating in said first discrete area but not said second discrete area.14. A method for forming a device for monitoring plural functions ofgoods comprising the steps of: (a) providing a substrate; (b) applyingto said substrate a universal bar code comprising a number of discretebars, some of said bars being printed with a polydiacetylene coating,said coating having properties of (1) changing from a first colorirreversibly to a second color immediately upon being subjected to aspecified temperature and (2), upon activation upon contact by anactivating agent, changing from said first color to said second color ata temperature lower than said specified temperature after a time delayof at least one hour; (c) applying said polydiacetylene coating to saidsubstrate in an area spaced from said discrete bars printed with saidcoating; and (d) applying said activating agent to at least some but notall of said bars printed with said polydiacetylene coating.
 15. A methodfor monitoring plural functions of goods comprising the steps of: (a)providing a substrate having first and second discrete areas; (b)applying diacetylene monomer to said first and second discrete areas;(c) polymerizing said monomer to form a coating of polydiacetylene, saidcoating having properties of (1) changing from a first colorirreversibly to a second color immediately upon being subjected to aspecified temperature and (2), upon activation upon contact by anactivating agent, changing from said first color to said second color ata temperature lower than said specified temperature after a time delayof at least one hour; (d) applying said activating agent to said firstdiscrete but not to said second discrete area; (e) maintaining orbringing said substrate to a temperature below said specifiedtemperature to cause that portion of the substrate contacted by saidfirst discrete area to change to said second color; and (f) thereafterheating said substrate to said specified temperature to cause thatportion of the substrate within said second discrete area to changecolor.
 16. The method according to claim 15 further including the stepof affixing said coated substrate to goods or to a container holdingsaid goods.